Solar eclipse of August 1st

The solar eclipse will be total in strips of northern Canada, Siberia (there will be a live broadcast from Novosibirsk since 9:00 am GMT i.e. 10:00 am British Summer Time!), Mongolia, China: see a Google map of the path and a NASA home page for the event (NASA TV was broadcasting this event, from 6 am Eastern [American] Time: double-click for full screen or watch a recorded video, 11 minutes).

East Coast (mostly Canadian) readers will have to wake up very early to see a (very weak) partial eclipse. Most European readers should see a partial eclipse more conveniently before the noon of their local time. In Czechia, at most 1/4 of the Sun disk will be covered around 11:45 am.

In India and Pakistan (see a preview from Karachi), you will see a partial eclipse late in the afternoon, local time. A special comment for Indian readers: there are no ghosts or bad rays associated with the event. It's just a fu*king Moon blocking a part of the solar light before it reaches the Earth! ;-)

But don't look at the Sun directly, without something like multiple strong sunglasses. The power may be limited but it is still the same strong Sunlight with the same fraction of UV rays. ;-) Limit direct observations of the Sun with your eyes to a few seconds: the eye will recover. After 30 seconds, you would pretty surely burn spots on your retina!

Click the animation at the top for more data about the event (Wikipedia). Finally, another cool fresh piece of news from the outer space:

Phoenix finds water (ice) on Mars.

Leaked Olympic ceremony: video

Press "Play" only if you want to see a sketch of the opening ceremony. The video was shot by journalists from South Korea that has no nuclear weapons. ;-)

Better resolution here... (click)

Tevatron favors light Higgs and MSSM

This is the very latest graph showing the top-quark mass (x-axis) and the W-boson mass (y-axis). The blue ellipse comes from the Fermilab:



You see that LEP I (CERN) and LEP II/SLD (CERN and SLAC) were undecided but the Tevatron (FNAL) seems to prefer supersymmetry: the blue Fermilab ellipse (68% confidence level) sits inside the green (MSSM) strip. That's surely not a reason to be 100% confident but it might be a hint. ;-)

See Pete Renton's PowerPoint presentation

Note that it is primarily the W mass that determines the expected Higgs mass and with the known data, the Higgs looks extremely light. The central value is below 100 GeV and at the 95% confidence level, the God particle sits below 154 GeV. When the direct searches are included in the calculation, the 1-sigma interval for the Higgs mass is 115-135 GeV. LEP could have discovered it if they could stop it later than they did.

95% percent of the Tevatron data are still waiting and it is expected that the precision of the W-mass (and other things) will be improved by a factor of three once all the data are processed. To make it clearer for some readers, using 20 times more data doesn't change their qualitative character: it only increases the accuracy by "reducing the noise", if you wish.

Incidentally, today, D0 at the Fermilab announced - in a press release - the discovery of three ZZ events extracted from 200 trillion events. ZZ events are very rare and somewhat similar to processes including a Higgs boson.

Via Tommaso Dorigo

Bangladesh gained 1000 squared km recently

Many climate alarmists, especially James Hansen, have been predicting a complete inundation of Bangladesh in this century. It has been one of the key examples how the "nasty" carbon-emitting rich nations are destroying the "nice" and poor ones. See, for example, page 11 of this paper by Hansen and thousands of web pages.



What is happening in reality?

As AFP, BBC, and others report, satellite images combined with old maps have revealed that the country has gained 1,000 squared kilometers since 1973 (more than 1 percent of the Czech Republic) and it seems to be continuing gaining landmass, roughly 20 squared kilometers per year.

Well, what was the mistake of the "scientists" who are predicting something completely different? Well, just as in many other cases, they have only counted contributions of one sign (negative sign) but they have completely omitted the contributions of the opposite sign (positive sign) that turn out to be completely crucial for the landmass budget, especially sedimentation and dams. New dams can reclaim up to 5,000 additional squared km in the near future, including new islands.

It seems that folks like Mr Hansen are the most influential pseudoscientific bigots and cranks that our civilization has seen at least since the 15th century, certainly when you measure their influence by the GDP fraction that they are able to destroy.

Yesterday I responded to Andrew Revkin's claims that similar new scientific findings "don't matter" for the "big picture" in the climate debate. Really? If one needs roughly 1 day to see that 10% of the "scary" predictions about the world are the opposite of the truth, how many days would you expect the life expectancy of this "science" to be?

Flash: Farm animals in Peru are threatened by an unexpected cold spell. Meanwhile, Al Gore places infant son in rocket to escape dying planet and reach a new home where the sky is clear and there are no Republicans.

Some biologists finally noticed that different climate models produce different results i.e. different answers to some biology-related questions that actually matter. Their proposed cure is to waste even more money for this pseudoscience.

Black holes: quantum mechanics at macroscopic distances

SlavaM has figured out what is the best hep-th paper today. This work by a Benelux (or, more precisely, Bene) collaboration is just amazing and I am surely going to write about it:

Jan de Boer, Sheer El-Showk, Ilies Messamah, Dieter Van den Bleeken: Quantizing N=2 multicenter solutions

Let me begin.

Can quantum mechanics reveal itself at macroscopic distances? The first obvious answer is No. Quantum mechanics governs the microscopic world. However, the former dean of the Faculty of Mathematics and Physics in Prague, Prof Bedřich Sedlák, used to be working on low-temperature condensed matter physics.

Mr Sedlák also liked the legs of a female classmate of mine - a friend who married my diploma thesis adviser (who was also a co-author of our linear algebra textbook, "We Are Growing Linear Algebra" - his name is translated as Gardener) - but concerning his discipline, he said that it is the best discipline of physics because

quantum phenomena may exhibit themselves at macroscopic distances.

He was talking about superfluids and superconductors, among other things. But he was really cheating. The relevant fields that mimic the wave function of the BCS pairs, to pick an example, are not really wave functions. They are classical fields. So what we're looking at is just another classical limit (arising from a particular combination of a large number of electron pairs), not a case of "macroscopic quantum mechanics".

Back to general relativity

However, many people have been suspecting for years that quantum gravity may offer us a more "genuine" example of quantum phenomena at macroscopic distances: holography and the information loss puzzle are two hints among many. Where do you expect quantum phenomena to become "really important"?

The old procedure to find the answer would follow the semiclassical approximation, the same approach to quantum gravity that allowed Stephen Hawking to deduce that black holes emit a thermal radiation back in the 1970s. You calculate the first quantum corrections - the semiclassical corrections - to the classical equations and if they are much smaller than the classical starting point, you decide that you can rely on classical Einstein's equations as far as all kinds of qualitative and approximate quantitative conclusions go.

In reality, this comment means that whenever and wherever the curvature is small relatively to the Planck scale (whenever the curvature radius is greater than the tiny Planck length), Einstein's equations locally work. Also, if you construct a solution to Einstein's equations that has a low curvature everywhere (and the singularities in the highly curved regions have a good "character", which is purely a qualitative condition), there should exist a corresponding state in the Hilbert space of a quantum theory. And parameters that look continuous in the classical theory should remain quasi-continuous in the quantum theory, with the spacing uniformly going to zero in the classical limit.

But is it true? Can you really trust classical Einstein's equations if these conditions are satisfied? Or is it possible for the quantum phenomena to modify Einstein's classical conclusions even in cases where an innocent semiclassical physicist wouldn't expect it?

You may guess why I am asking these questions. The information loss paradox may be viewed as the first reason to believe that nonlocal phenomena (which are clearly incompatible with the principles of classical general relativity, including causality) may enter the scene at macroscopic distances, in order to preserve the information. But that's just a guess whose explicit description is not fully understood - which is why many people say that the information loss paradox hasn't been fully solved.

However, the present authors demonstrate that there exist fully controllable situations in which quantum mechanics influences physics at macroscopic distances. In some sense, they seem to confirm and illuminate the fuzzball paradigm by Samir Mathur. But their approach is slightly different and more explicit.

The setup

What black holes do we consider? It is still a kind of "general relativity in four dimensions coupled to other fields". But it is useful to consider highly supersymmetric low-energy theories resulting from highly supersymmetric compactifications because the supersymmetric nonrenormalization theorems allow us to describe physics in many ways (including configurations of D-branes and strings) and many physical quantities may be calculated exactly. The most helpful class of such compactifications is type IIA string theory on the four-dimensional Minkowski space multiplied by a six-dimensional Calabi-Yau manifold.

We have encountered these compactifications in the context of the Ooguri-Strominger-Vafa (OSV) conjecture. We're still interested in the same backgrounds and the same solutions.

These theories have 8 supercharges, twice as many as needed for a viable phenomenology. So they are called N=2 vacua in four dimensions and they have the "ideal" amount of supersymmetry that is neither too constraining - which would make the results (such as the moduli spaces) trivial - nor too unconstrained - which would make them uncalculable. As Paul Aspinwall used to say, the real world only has one half of this ideal amount at most but it was not his fault (a mild criticism directed at his colleague God). But the solutions to these N=2 supergravity equations can also be interpreted in a five-dimensional language: the black holes can be "lifted" to M-theory which has one more dimension. The corresponding five-dimensional supergravity is called N=1 d=5 supergravity because 8 supercharges is the minimum supersymmetry you can get for five large spacetime dimensions.

The relevant black hole solutions are BPS: they preserve one half of the supercharges of the background, i.e. 4 supercharges.

This is a sufficient number of supercharges for the number of black hole microstates to be constant as you change the string coupling. In fact, the whole phase space is identical at weak coupling and strong coupling and the authors explicitly check this fact in this paper, too.

What phase space am I talking about? Well, you must first write down the black hole solutions. They are multi-centered solutions with many charges described in terms of split attractor flows by Frederik Denef. You may imagine that these black holes look like threshold (=zero binding energy) bound states of many mono-centered black holes with some charges so that the charges add up properly.

You might expect that the space of these static solutions is a configuration space of these objects and you have to add some velocities (or, equivalently, canonical momenta) to get a phase space. However, these black holes are not really static because they carry the angular momentum (a typical feature of objects with both electric and magnetic charges, i.e. dyons). And with a nonzero angular momentum, the space of solutions is actually not the configuration space but the phase space itself! You don't have to add anything. It's already moving.

This observation is related to the fact that "x" and "p" eigenstates are not normalized to unity (but rather to the delta-function) but "j, j_z" eigenstates usually are. Alternatively, you may say that different components of the angular momentum don't commute with each other so they're the canonical momenta of other components. Once again, the solution space is the phase space.

The near-horizon geometry of these black hole solutions is eleven-dimensional, namely "AdS_3 x S^2 x CY_3" with M-theory in the bulk. Via the AdS/CFT correspondence, this gravitational theory has a conformal dual which is called the Maldacena-Strominger-Witten (MSW) (0,4) superconformal theory, describing some kind of membranes living in the Calabi-Yau background whose near-horizon geometry is the "AdS_3"-type space. Note that MSW is symmetric under a rotation by pi. These are big names with a lot of symmetry, indeed. ;-)

OK, so the present authors are now able to find the exact form of the solution space i.e. the phase space. The resulting manifold happens to be a toric one - you can describe it by a toric diagram (where the coordinates correspond to some "radial" distances and toroidal fibers describing the complex phases are added at each point; various cycles of these toroidal fibers can shrink to zero at special points, the boundaries of the toric diagram, according to well-known rules of toric geometry). It also happens to be a Kähler manifold and the authors explicitly find the Kähler potential. Some links of the space to weighted projective spaces are mentioned, too.

Fine, so the solution space is exactly known. If you want to be accurate, there is a subtlety here because in order to find the microstates corresponding to the black hole, you should first construct the full quantum theory - by quantizing the full phase space of supergravity - and take the subspace of the Hilbert space, describing the black hole microstates, at the end. Instead, they truncate the classical theory at the beginning (into the space of solutions) and quantize it as a phase space. It's not quite the same thing because the operations don't commute but it's close. The dimension of the solution space is a linear function of the number of centers.

Shocking conclusions

So these difficult problems turn out to be exactly solvable although, using Barbie's observations, the math class is tough. But what are the surprising qualitative consequences of these results?

There have been many types of the Denef-like solutions with unusual qualitative properties. For example, some of them allowed the "throat" to be infinitely long. In such a long throat, you could have excitations with an arbitrary i.e. continuous momentum. That would lead you to believe that the spectrum of the CFT should include a continuous portion. That looks strange.

Fortunately, the Benelux authors find this not to be the case. Quantum mechanics actually imposes an upper bound on the length of the throat. Quantum mechanically, the throat is not infinite but finite! That's great because the spectrum of the dimensions in the MSW theory can stay finite, as every sane quantum person would always expect.

Similarly, they resolve another old paradox involving barely bound black holes. Using the classical equations, you may find solutions that look like barely bound states where the components are arbitrarily far from each other. That also looks paradoxical because there could be infinitely many such increasingly delocalized bound states. In this case, quantum mechanics cuts the maximum distance between the components of the bound states in the black hole.

They see these things by simply looking at the geometry (and measure) induced by the symplectic structure on their solution spaces because they know all these things explicitly.

What is the general lesson? The general lesson is that in quantum gravity, the number of degrees of freedom is often much lower than what you would need to realize all of your fantasies based on classical physics. The entropy bounds and the holographic principle were the old moral examples why it is so.

The new Benelux paper gives you a new and, in some optics, more concrete picture why not all of your classical fantasies are allowed. Why is it so? Simply because you often don't have enough quantum phase space (not even one Planck volume, up to powers of (2 pi), necessary for one quantum microstate) to realize them.

A priori, this comment could sound crazy to you. If you have large objects, the corresponding phase spaces - parameterizing things like the distances between the components of a bound state - are also large. And if they are large, these phase spaces will have a large enough volume in all of their regions to represent all the classical geometries rather faithfully.

But the vague argument above is actually incorrect. Long distances on the phase space actually don't imply large volumes. ;-) Picky mathematicians would always know that they don't but most physicists would suspect that the mathematicians' counter-examples are inevitably pathological. But they can't really be that pathological because they appear in the description of some of the most canonical black hole solutions in supergravity and string theory.

A toy model of the small volume

For example, imagine that the phase space has two coordinates, "x" and "y". The coordinate "x" is a real number greater than a positive number "epsilon" while the coordinate "y" is real and periodic with period "1/x^2" (a fiber). The phase space is a tube that is getting thinner. For too high values of "x", you won't simply have enough volume in the phase space: the integral of "1/x^2" from "X" to infinity is equal to "1/X".

If "X" is substantially greater than one, the integral is smaller than one (and than 2 pi) and you will simply not find a single microstate that corresponds to the points of the classical configuration space, even though classically, "x" could have been arbitrarily high. For arbitrarily high values of "x", the corresponding classical configuration looks smooth and fine. Nevertheless, when you actually try to create a quantum microstate exactly at this point, with a high value of "x", you will obtain a violently fluctuating monster that doesn't resemble the classical smooth geometry at all.

The microstate is actually smeared out along a huge distance in the phase space. A few hours ago, I was explaining Benjamin in the fast comments that he could always imagine that the uncertainties of canonical coordinates and canonical momenta both go like the square root of Planck's constant which obeys the uncertainty relation while all the uncertainties still go to zero in the classical limit. Well, it's no longer the case here. If the canonical momenta have a very short circumference, the uncertainty of the corresponding canonical coordinates must be macroscopically large!

I believe that this major conclusion may be imported into other contexts in quantum gravity.

Once people look at them carefully, they could also understand the origin of holography (and the Bekenstein-Hawking entropy for general backgrounds) somewhat more constructively. What do I mean? The surprising feature of holography is "how do all those numerous degrees of freedom - that a priori seem to be associated with the large black hole interior - disappear?" And the answer could be that they don't really disappear but if you construct the corresponding phase space (whose cells form a basis of the Hilbert space), you find out that the volume of the phase space is much lower than you expected and the calculation reduces to those simple phase spaces that lead to the finite "S=A/4G" entropy.

Also, this result perhaps clarifies some of the confusion that many of us have had about the fuzzball proposal by Samir Mathur. We were asking him: shouldn't the black hole really look like the empty black hole solution we learned as undergrads, because of locality? How could all the mess of horizon-free smooth solutions replace the black hole geometry, including a singularity and a horizon, that seems to be weakly curved everywhere and that should be reproduced by general relativity?

The partial answer is that the black hole microstates can perhaps be still parameterized by a phase space - ideally, a subspace of the phase space of supergravity (even though some other, stringy coordinates could be needed in the general case) - and all the classical fuzzball solutions are still in it. But none of them gives rise to a well-behaved, stationary black hole microstate because the quantum microstates can only be obtained by combining many classical configurations that macroscopically differ because the states supported on a phase space region with a "small diameter" simply have a lower volume than required for one microstate. It doesn't quite explain why an observer will see the "boring", old-fashioned black hole interior with the singularity. But it does explain why he will never see the sharp fuzzball geometries inside.

This effect could be important for our understanding what really happens when you cross a black hole horizon. I guess that some previously confusing things start to make sense.

LHC: FAQ

Update: Physics World spreads a rumor about the first proton beams to be injected on August 9th into parts of the tunnel and on September 2nd-3rd to the whole ring.

Original text from July 28th: Martin Coles at The (Montreal) Gazette wrote a couple of excellent articles about the Large Hadron Collider. Click at the following:

Frequently asked questions (illuminating, a lot of understandable numbers!)
Deep thinking (from Galileo to the LHC, a story)
In their realm, outside Canada (Montrealers at CERN)

For a photographer and a journalist, these sensible articles are extraordinary and deserve an explanation. The main explanation is probably that Martin Coles has studied math and philosophy in Cambridge, Old England, so he is not quite just a photographer or a journalist. ;-)

Incidentally, all eight sectors of the LHC except for "78" are already below the temperature of 5 K, usually close to the final 1.9 K. Only the "78" sector is at 15 K in average (update, July 30th: close to 5 K, too). It should be cooled down soon.



I don't really like rap but if you do, play the video above. Ms Alpinekat explains the basic purpose of the four LHC experiments very well.

Hat tip: Tommaso Dorigo.

Slavery: the House apology lacks logic

The U.S. House of Representatives has apologized for slavery and segregation.

Full text (click)

Besides dozens of "Whereas" sentences summarizing and emotionally interpreting some random historical events whose precise role is unclear to me, the resolution says:

That the House of Representatives

1. acknowledges the fundamental injustice, cruelty, brutality, and inhumanity of slavery and Jim Crow;
2. apologizes to African-Americans on behalf of the people of the United States, for the wrongs committed against them and their ancestors who suffered under slavery and Jim Crow; and
3. expresses its commitment to rectify the lingering consequences of the misdeeds committed against African-Americans under slavery and Jim Crow and to stop the occurrence of human rights violations in the future.

The point (1) is kind of fine except that the same things have already been pretty much done in the 1860s and 1960s, respectively, when the previous legal system was changed. So the point is redundant. Of course that as the society diverges from the old order, many things will look increasingly more alien to the newer generations. Is that surprising? Does America need a resolution about it? Will the Congress also denounce scalping by Native Americans as fundamentally cruel, brutal, and unjust? By the way, if it won't, what's exactly the difference? Why is it that segregation is denounced but scalping is not?

It is the point (2) that is logically confusing and morally controversial. The U.S. Congress, a body that includes black Americans, is apologizing for slavery. Either these black lawmakers are apologizing to themselves or the U.S. Congress implicitly (and incorrectly) states that it is still exclusively controlled by the descendants of slaveowners who are the only ones who have the "credentials" to apologize.

Clearly, the U.S. Congress in 2008 has nothing to do with slavery. None of the current lawmakers helped to codify slavery or segregation. Moreover, the ancestors of many current lawmakers have never seen (or participated in) slavery because they didn't live in America 140+ years ago. The U.S. Congress hasn't even inherited slavery because it's been abolished a long time ago. Moreover, much of the slavery occurred before the United States were even created (together with the Parliament). So in what sense the U.S. Congress has the right to apologize?

Who is apologizing to whom?

I suppose that at the end, the only meaningful and remotely justifiable interpretation is that the descendants of white Americans who used to own slaves (or at least those who indirectly helped the slaveowners) are apologizing to the descendants of black Americans who were the slaves (or their relatives).

At least I would find it fundamentally unjust and crazy if e.g. the typical Russian or Chinese Americans - and let me not forget about them: Czech Americans, too! - whose ancestors have never owned any slaves were apologizing to anyone. They have nothing to apologize for because they haven't done anything wrong - and even if you argued that a person is responsible for all the acts of his or her ancestors, not even their ancestors have done anything wrong to the blacks.

Should they apologize just for being white, i.e. for having this unpopular (white) skin color? For having "cousins" (as defined by common ancestors who lived a few thousand years ago) who had something to do with slavery? This would be an extremely flagrant case of racism, indeed. In that case, it would be equally "justified" for all blacks to apologize e.g. that their crime rate has always been much higher than for whites. Moreover, blacks and whites are also cousins, as long as you believe Darwin. ;-) You must just go tens of thousands of years further to the history to find the common ancestors.

That means that in order to see who is apologizing to whom, one must trace the family roots of each individual back to the 19th century, look at those who lived in America at that time, and apologize. Does someone expect that such a profound return to biological ancestors who lived 140+ years ago will help to further reduce the boundaries between the races? I beg to differ. The historically created boundaries only disappear when the past becomes irrelevant.

What the resolution can do is to increase the tension between the races. The point (3) sketches how it may take place. The blacks will suddenly be able to argue that whatever they don't like are "lingering consequences" of slavery and segregation, as described in the third point, and they will demand to have "higher" human rights than all the whites in order to "rectify" those consequences. The precise extent to which one can "rectify" is obviously ill-defined (and this ill-definedness is a very bad thing in the legal system) but some of your black employees or students may start to do these things all the time. Of course, sensible whites will object because such a new form of racism would be unconstitutional and outrageous. Some white PC people may wish to declare a new era of reverse racism but I assure you that not everyone in America is PC or crazy and it is both non-democratic and dangerous for the PC people to assume otherwise.

This arrangement with asymmetric human rights of individuals can't lead to anything good, especially not under a black president. The only way to protect a nation against injustice is to have and enforce laws that guarantee justice and to gradually move all the historical injustice from the current life to the history textbooks where it will be written forever. History cannot be overwritten, sorry.

Collective guilt

Finally, I want to express this opinion of mine in one more way. The resolution is an obvious example of collective guilt because it intends to punish people for their skin color. You know, the principle of collective guilt is an extremely subtle and potentially dangerous paradigm. For example, in 1945, the Czechoslovak politicians and judges decided it was impossible to individually punish every individual Sudeten German for their Nazi acts before and during the war because there have been way too many of them and the number of Czechoslovak courts and prisons wasn't infinite.

So the expulsion and other forms of collective punishment were chosen instead, in order to "approximately" settle the injustice that has taken place in between the communities. The most peaceful exceptions - the Germans who could prove that they fought against Nazism - were exempt and they could stay in Czechoslovakia. But these policies - the Beneš decrees - were still based on the principle of collective guilt. I am convinced that back in 1945, it was a very sane decision to do these things and it is extremely dangerous to question the decrees today because one could revive the ghosts of many old conflicts that should be forgotten or, more precisely, disconnected with the current political issues. But a descendant of Czechoslovak citizens who supported the post-war policies certainly can't feel 100% saint about the decrees. They were only justified by the exceptionally difficult situation a few months after the greatest world war ever.

But if someone replaces a few months by 140+ years (today, when all the actors in the theater of slavery are safely dead) and applies the same principle of collective guilt to slavery, it is clearly a decision that cannot be justified by any exceptional situation and that cannot do anything good for justice and for the peaceful co-existence of people of different skin colors. So I believe that the resolution is an act of racism and it suppresses the individual rights and the individual responsibility for people's acts.

And that's the memo.

Revkin & inaccuracies in the media

Andrew Revkin wrote an essay about the way how the media deal (and should deal) with uncertainties in science:

Climate experts tussle over details, public gets whiplash (see also his blog)

RealClimate and BackReaction are among the blogs that have responded.

Andrew Revkin, a moderate climate alarmist, is worried that the uncertainties and fluctuations of the scientific results reported by the media - for example constantly changing statements about the warming/hurricane link and about the melting Greenland ice - reduce the confidence of the public in some "basic" propositions that he considers settled, especially his opinion that "we should act to stop climate change".

Well, that's too bad if he wants these "big questions" to be unaffected by the scientific results because this "irrelevance of scientific results" is the main reason why we say that climate alarmism is a new form of religion. Policymaking that is based on real science certainly should be affected by new scientific insights and it is very correct if the public is affected, too.

Although Revkin wrote his article in order to defend the highly irrational "action to stop climate change" regardless of any scientific results and his article will be viewed as tendentious and outdated as soon as the current climate hysteria will fade away (and many of us know that it is tendentious and outdated already today), his text nevertheless opens an important question:

How should the media report the uncertainties about scientific propositions?

In principle, every well-defined "Yes/No" question about Nature (and sometimes even the society) has a sharp answer: either it is "Yes" (the probability that the statement is correct is 100%) or it is "No" (the probability is 0%). In reality, scientists (and people in general) aren't sure about the answer. So their confidence is a number in between 0% and 100%. Some questions are close to 0% or 100% - those that have been pretty much settled - while other questions are closer to 50% - especially those that are not settled and that the scientists are trying to answer right now.

Let us assume that the "best confidence level" P, the probability that a particular proposition (e.g. "a warmer climate will bring more category 5 hurricanes") is correct, calculated by taking all known evidence "optimally" into account, is a number that objectively exists. Instead of the probability "P", we could also be talking about the "average expected value P" of some continuous quantity. It plays a very similar role in the following text.

What should the media be doing with this number? Well, the ideal newspapers or TV stations are able to pick the right scientists, to organize their own scientific calculation of the confidence level, and to present the true picture of reality, including the correct number "P", reflecting the best up-to-date science, to their readers or viewers. ;-)

As you may guess, these ideal newspapers and TV stations don't exist. They typically report an incorrect "P" that can deviate from the correct one in both directions. The media can make certain statements

1. look less certain (closer to 50%) than what science says,
2. look more certain (further from 50%) than what science says.
   

This classification was about the value of "P". However, there are several types of imperfections that prevent the media from giving their readers and viewers the most accurate answers. Even if we are talking about qualitative and not quantitative propositions, the most important classification of the errors is to:

1. Statistical errors
2. Systematic errors

Statistical errors arise because the journalists are not able to reach the best scientists and listen carefully to them. They only have the access to the local scientists or otherwise accessible scientists. A certain amount of "noise" is inevitably added because the journalists are sloppy and their understanding is imperfect. The scientists' way of talking is imperfect, too. Personal idiosyncrasies of the journalists contribute to this noise, too. News stories written by new journalists that are largely based on the stories by the previous journalists, not a direct interaction with science, further increase this noise. But if you assume that the journalists have no reason to deform the scientific results in a particular direction, this noise largely cancels if you combine many sources.

The most trustworthy media are expected to have a high signal/noise ratio: their coverage should be more accurate than the coverage by others. They should give you the most accurate idea what the number "P" is, even though the number can be encoded in words and the precise meaning of various words such as "very likely" may often be misunderstood. However, one must realize that which media are the most trustworthy ones is a dynamical question whose answer can be changing with time. The New York Times may be doing relatively well but it was never guaranteed and it is still not guaranteed that the paper would remain one of the most trustworthy sources forever.

It makes no sense to dream about a world where all media are completely accurate. You can't have such a thing in a real and free society. There will always be these statistical errors and noise. Demanding readers will always be preferring accurate sources; other readers will look for the less accurate ones, either because they don't care about the accuracy or because they can't distinguish the accurate sources from the inaccurate ones.

In some sense, the systematic errors are worse because they don't average out. They correspond to biases that always go in the same direction. If you read hundreds of stories about a topic and take the average "P" from these stories, you can still have a very distorted opinion about the true value of "P". For example, a vast majority of left-wing blogs and even the mainstream media will always tell you that the climate phenomena will be more catastrophic than what science actually says. They have all kinds of reasons why they're doing so: catastrophic and oversimplified stories sell well. Moreover, many journalists are activists who want to reduce the human freedom and to increase the regulation of the world. Or at least their bosses and colleagues want their whole teams to help to increase the regulation.

Systematic errors are bad because they can systematically "push" the answers in the same direction and lead the readers to a distorted picture of reality. However, there is a sense in which the systematic errors are easier to deal with. Imagine that you have a source with low statistical errors but a nonzero systematic error. For example, it always tells you that the number "P" is 10% higher than it actually is. Everyone knows that a newspaper has a left-wing bias. A wise reader can figure out that it is the case and develop a new algorithm that subtracts 10% from the number "P" that he can see in the source.

Well, in the real world, the bias is usually much higher than 10% (and depends on the particular question in ways that are somewhat hard to predict) and it is harder to subtract the right amount. But I wanted to show you that such an approach is possible in principle. It's like adding light to a photograph that was too dark (or subtracting light).

Among other things, this comment means that if the journalists are trying to change the opinions of their readers by systematically pushing their stories in one direction, they will fail if the readers are rational and unbiased because the readers will eventually learn how to deal with this systematic bias. That's one of the reasons why your humble correspondent can read the New York Times and treat it as a useful source of information: it has rather low statistical errors while most of the systematic errors (usually connected with politics) can be expected and subtracted.

Of course, if the readers are gullible or if they are biased themselves, they will end up with biased opinions. But it's important to notice that the newspapers can only manipulate readers who are either intellectually limited or who were biased from the very beginning, at least in the long run. You can't really permanently "convert" rational readers by writing biased stories.

And the education systems should try to educate citizens who are not gullible and who can't be manipulated easily: citizens who are able to subtract the bias if they clearly see one (or have solid evidence that it exists).

Changing stories: frequency and amplitude

One of the important points that Revkin has addressed is that the stories about the hurricane/warming link, among many other topics, change rather frequently. The stories about the healthy lifestyle are even more dramatic in this sense: is it healthy to drink water even when we are not thirsty? Yes, no, yes, no. In the climate context, Revkin is worried because the readers could start to think that science is uncertain.

Well, the main problem is that science is uncertain and far from settled, indeed. Some topics are more understood and others are less understood. But none of them, especially not those that are discussed by scientists near the cutting edge, are completely settled. As the scientists keep on doing their research, their best estimates of the probability that the warming increases the hurricane rate (or the best coefficient determining how much the hurricanes increase or decrease per one degree) is changing. Revkin wants to suggest that these changes don't influence the "big picture", namely that we should "act".

But of course that they do. The answer to the question "should we regulate CO2?" is a complicated function of other, more elementary and specific answers (including the hypothetical hurricane/warming link). It is not an answer that can be determined before others. It simply couldn't have been determined yet (because the independent variables such as the hurricane/warming coefficient have not yet been settled) and the people who think that it has already been settled are profoundly unscientific.

About 20% of the explanations why a slightly warmer climate is supposed to be dangerous has been based on the hypothetically increasing hurricane rate. In 2005, after Katrina, this ratio went rather close to 50% because some dishonest ideologues and pseudoscientists found the link convenient because of the people's immediate emotions. This was a temporary peak but even 3 years later, it is damn important whether this effect (a causally justifiable correlation) actually exists or not. It decides about 20% of the justification for the "action".

The question whether the Greenland begins to melt quickly (and to increase the sea level) decides about another 20% contribution or so. Just ask "why should the warming be a bad thing?" and see how many people will start to talk about the hypothetically increasing (or accelerating?) sea level. If you combine these two uncertain effects, that's already nearly 1/2 of the motivation to "act". And there are similarly important questions that are uncertain. How the hell can someone say that these individual scientific questions of higher-than-medium importance don't matter (as soon as the answers start to be inconvenient) for the debate? They obviously do matter. For example, if five such answers change the sign in the same direction, it may become more rational (but not quite rational) to attempt to warm up, and not cool down, the climate. And that's a big difference.

But these are the obviously tendentious, cheap, and outdated aspects of Revkin's essay. Let's look at the more general questions that are unaffected by Revkin's irrational climate change quasi-religion.

Once we accept that the scientific opinions actually keep on changing, what should the media be doing about these changes? Well, they should report them if they actually exist. And the education systems should teach all students that science may be changing and to rationally estimate how frequently and how much it can be changing. It is not a good idea to systematically teach the public that science (or its particular discipline) is more certain and fixed than it is; it is an equally bad idea to teach the public that science (or a discipline) is more uncertain and variable than it is.

The media should report the changes according to reality. Again, the ideal media don't exist. The media may err in both directions:

1. They don't report changes and pretend that science is more "constant" than it is
2. Their reports are changing more rapidly (or more frequently) than the actual scientific results.

In the first case, the media represent dogmatism. They are slow, they don't want to look at the reality. There are often journalistic zealots behind this highly inertial behavior and sometimes there are understandable reasons how did these people get there and why they act the way they act.

In the second case, the media suffer from a short memory and mood swings. The reason behind the frequent mood swings are often increased statistical errors that we discussed at the beginning or the desire to write diverse stories that differ from the previous ones. Sometimes, a female or male journalist who only talks to a limited local circle of sources but who frequently changes her or his friends or "friends" may be the culprit. Media-made controversies, backlashes, and back-backlashes belong to this category.

So once again, the media can be wrong in both ways. They can present a more dogmatic picture but also a more fluctuating picture than what science actually says. These errors may become systematic: some media may be systematically dogmatic (or conservative, with a specific meaning of this adjective) while others want to catch up with every newest fashionable trend. Both adjectives, "conservative" and "fashionable", are meant to be negative labels in this context: they are different types of biases.

More importantly, the media can have - and, in fact, almost always have, because of understandable reasons - another type of a systematic error: the uniformly positive (more likely than negative) correlation between the frequency of changing their stories and the desired political or societal or egotistic impact of the latest changes. What does it mean? What I mean is very simple so let me use simpler words.

If science changes in the direction they like, they report the changes very quickly and amplify them. If science changes in the direction that they don't like, they hesitate, and even if they report the change after some time, they don't give enough attention to it and they never present it as a clear-cut story.

It is not hard to see that virtually every newspaper tends to behave in this way. This behavior is another kind of systematic error. Once again, good and objective journalists should be more immune against the temptation to act this dishonestly and good and sensible readers should prefer the newspapers that don't have similar systematic errors.

It is important to note that the newspapers don't have to be explicitly lying in every article (and not even a single article) for their coverage to be dishonest. If you can statistically reveal that a certain type of stories is reported much faster, much more loudly, and with much less uncertainty than another type of stories, it is enough to see that the newspaper is biased.

Summary: the future

To summarize, the inaccuracies and biases exist, they will always exist, and they can have many forms. Sensible readers should know how to evaluate the news stories and eliminate the systematic biases. If the systematic biases are too high, they should prefer sources with lower biases. The education systems should teach the students how to choose their favorite trustworthy sources (much like they should prefer accurate clocks or anything else) and how to eliminate their residual biases.

If you're an optimist, you can predict the following: the intelligence and the rational behavior of the public will be increasing. Among more intelligent readers, the accurate and unbiased sources will be winning. Both statistical as well as systematic errors will be dropping in average. At the end, the serious media will pretty much report exactly what science actually says. There will still be fluctuations but these fluctuations can't be eliminated because science is not over (and it will never be over): the fluctuations are real and they always exist, except for the old quasi-settled facts that should be written in textbooks, not in newspapers.

If you're a pessimist, you can predict that the readers will be unable or unwilling to uncover, reject, or subtract biases and errors. The inaccurate media will be flourishing, the pressure on the media to be accurate will be dropping and criteria different from the truth and accuracy will become more important. All kinds of non-scientific pressures will start to dominate the material that is actually being published. At the end, the media reports will have nothing to do with science and the society will return to the Dark Ages. We may still be using advanced technologies that are being developed by profit-driven companies that are interested in science for financial reasons. But everything that is influenced by the public opinion will become mostly unscientific.

Am I an optimist? Well, I have some worries but I am more likely to be an optimist than not. Natural selection (even in the context of knowledge) naturally keeps on improving things, including the media. If the public is a bit intelligent and if there is at least some pressure on the public to think and act sensibly, they will learn how to search for high-quality information and this demand will influence the supply side, too. Such dynamics won't occur if one or more of the following things becomes true:

• virtually all the people become too inherently stupid
• the people won't have any reason (pressure or innate interest) to make their opinions compatible with science: for example, rational reasoning will become really unpopular and unstrategic
  
• the whole societies will make it impossible for the information to propagate: I am talking about extreme plans of Nazis, communists, or environmentalists to ban certain kinds of public speech which, I hope, will only be realized very locally and very temporarily and won't affect the world globally again.

We will see.

Smartkit: SpinIn game

Full screen (click)

Press arrow keys to determine the direction of gravity and get the smiling box out of the rectangle.

Low climate sensitivity and other inconvenient truths

In case I haven't yet linked it, here is the English translation of an introductory text of mine about climate change:

Word file, PDF file (click)

It is several months old.

Leonard Susskind, global warming, and groupthink

Leonard Susskind's new book is selling very well. An amazon.com user named Collosus [sic] wrote an interesting 3-star review:

Susskind mainly does well here. He takes the time to give a pretty good qualitative grounding in a number of important concepts. His extended discussion of entropy is particularly well done and does provide a good foundation for understanding the black hole information destruction question. However, he cannot resist making the political statement here and there and, while his physics may be sophisticated, those statements quickly indicate that his politics isn't.

His statements around global warming in particular reflect a willingness to accept assertions without any scientific rigor behind them. This reflects something that is a paradox with a lot of these popular physics books, particularly when they are written by members of the academy: it is often difficult to distinguish between the real scholarship, on the one hand, and the prevailing academic herd orthodoxy, on the other, in which many assertions are simply accepted without the requirement of evidence, much less proof.

This is a phenomenon that Lee Smolin discusses perceptively in his very good "The Problem with Physics."

Other issues include the writing, which is at best pedestrian (don't expect the literary gifts of a Brian Greene) and the insistent name dropping, apparently intended to remind the reader of his membership in the pantheon with Feynman and Hawking. Susskind's dismissive attitude towards religious scholarship (including a particularly insulting (and utterly gratuitous) passage regarding Talmudic scholars) is also troubling.

However, these is relatively minor annoyances if you're there for the physics. This book is still reasonably useful and is worth the time to read.

As a physicist, Leonard Susskind is on par with Stephen Hawking even though most media tend to obscure such things. And many other physicists besides Leonard Susskind would have serious doubts about Talmudic scholarship, too. ;-) But of course, I want to focus on global warming and groupthink.

Scholarship vs herd mentality

I completely agree with the reviewer that the difference between real scholarship and groupthink is often (but not always) obscured in popular books. But if the authors are serious scientists such as Susskind, this fuzziness is due to the popular character of the books, not due to the authors' inherent scholarly sloppiness. For example, Susskind would never include the global warming orthodoxy into his physics papers for experts. It simply seems difficult to explain certain things to the laymen - where every statement in science comes from, how solid it is, and so on. Scientists usually think that the laymen are not even interested in similar things: sometimes they underestimate the laymen, sometimes they are right. Leonard Susskind surely thinks that it is important to mix physics with anecdotes and social topics - he explicitly says so - and the boundaries may often become fuzzy.

But much like a majority of scientists in the Academia, Leonard Susskind is "progressive" (far left) when it comes to politics and global warming is one of the main incarnations of modern leftism. It is about the regulation of the world. The basic questions (or, more precisely, the key answers) have nothing to do with science and they are not allowed to be questioned by science.

And I am confident that Lenny, in essence, realizes these points. I am confident he knows that the global warming scientists are simply not at the scholarly level of the world's top scientists: 90% of them were hired during the last decade and they were simply tasked to "prove" the pre-determined existence of man-made global warming from the very beginning, not to objectively look for answers to scientific questions.

I am confident he realizes that what he writes about the climate is not supported by his (or someone else's) serious scholarship but by his political agenda and by the herd mentality that he happens to share with most of the Academia, for purely political reasons. And he is able to divide these things from the arguments about black holes if you seriously ask him in privacy.

When I was an undergrad, I used to interact with a group of Christians rather intensely. Many of them were kind of friends. And many of them were extremely rational (and sometimes even excessively materialistic) in their everyday life and many of them were even very good in programming and other things. But when it came to questions that had religious implications (such as the origin of species), the rationality simply evaporated. They hit a very hard mantinel. Science is useful but big questions such as the origin of life simply don't belong to science: they belong to the set of basic beliefs. It is God who created the animal and plant species, one by one. You can't simply betray God. Amen.

The case of global warming and equality is completely analogous. The left-wing believers are ready to use the scientific method to analyze all kinds of small questions and phenomena. For example, they may scientifically study the gaugino masses or the squirrels in New Jersey that almost no one outside their narrow field cares about.

But in their viewpoint, science has its boundaries, too. When it comes to the fundamental question such as "should the government remove all inequalities between the people?" or "should the government regulate?" or "should the government pay huge and increasing money to the Academia?" or other questions that could directly influence the previous three, there is no room for a scientific debate. The debate is over before it started. These are pre-determined dogmas. "Wrong" answers would make all of their life and work meaningless.

For example, one can talk about all kinds of somewhat detailed climatological questions with Andy Strominger, too. But he would explicitly make you sure that these arguments don't really matter because the regulation and redistribution are good things even if the whole "science" is completely wrong. That's how it works. Science is irrelevant here. In the following day, he would have a lunch will Al Gore and a dinner with Naomi Oreskes. ;-)

Smolin and groupthink

The reviewer's comment painting Smolin as a warrior against groupthink is amusing. It's not enough to be a high school dropout (see also NYT) and a retired revolutionary to be immune against groupthink. In fact, most other well-known high school dropouts suffer from groupthink, too. And the Cuban Parliament is full of retired revolutionaries but it also suffers from groupthink. ;-)

Lee Smolin is the ultimate example of groupthink, politicization, and intimidation in science. When I wrote a completely objective, polite, and innocent review of his book, explaining why his opinions about physics are nonsensical, he teamed up with a few additional enemies of string theory and sent letters to several senior physicists at Harvard (they chose the "most progressive" ones) who were kind of above me at the time, in a clear attempt to cause problems to me personally, behind the scenes, and to silence me. He wanted the whole public not to be told the reasons why (and the very fact that) almost not a single achieved physicist considers Smolin a serious scientist and, although it almost sounds as a giant conspiracy theory ;-), Smolin essentially succeeded.

In the letter, they also argued that I had to be a sexist and a racist just because I find it unacceptable for physics to be controlled by the ideology of feminism and similar pseudointellectual junk. They were simply abusing the fact that much of the Academia believed in far left-wing causes to personally hurt someone. I am not sure whether they were able to separate string theory from their left-wing politics but they surely didn't want to separate them. And this is what the far leftists are doing all the time. These are methods of Gestapo informers and you can't be surprised that I view Smolin, Woit, and a few others as symbols of moral deterioration and totalitarian tendencies in the Academia. Having some experience from communism, I couldn't ever work in an environment that allows this disgusting immoral crap to flourish.

You know, every good physicist I have known kind of knew (and knows) that Smolin was a sort of crackpot. But their shared left-wing politics has always been more important for them.

Smolin is the ultimate builder of a "consensus science" who would never tolerate any disagreement with his own opinions that are, when it comes to politics, even more "progressive" than Susskind's. And he writes these things very explicitly in his book, too. I am shocked that so many people haven't understood what he actually wants. In the book, he proposes to create a group of "scientists of good faith" (apparently including himself or even led by himself) who could never be criticized and whose (usually very dumb) theories could never be questioned. This group is subsequently supposed to search for "original" thinkers, i.e. mediocre pseudointellectuals who are exceptionally good in licking the butts (and sometimes not only butts) of the "scientists of good faith" such as Smolin: this ability is referred to as the "social skills" over at Backreaction. (They often like to lick them, to reward Smolin's promotion of their crackpot papers.)

In reality, he also surrounds himself with many people, usually females, who are not up to their job but who mostly say "Yes Mr Smolin". Physicists with IQ above 120 could easily explain him what are the problems with every new glub-glub-glub paper that he writes and what are the correct answers to some questions he can't even formulate well - but he doesn't want to listen to the people who know what they're talking about. He is not interested whether his theories (and others) are actually correct or not. Instead, he wants to enjoy (a completely undeserved) privileged status of a "scientist of good faith". And because of the support from the extremely limited journalists and laymen whom he is able to manipulate single-handedly, he actually does enjoy the status even though he has never contributed anything valuable to science.

This is not how real science can work or should work even though some disciplines that have become pseudoscientific obviously do operate in this way. I hope that the bulk of theoretical high-energy physics won't join them.

Summary: which disciplines are threatened

So the reality of groupthink in the Academia is that there are many disciplines where it plays a role. The closer a discipline is to the media and to the activists, those who care about the "character" of the results and the social "applications" but who don't care whether the results were derived properly and honestly, the more un-scientific mechanisms influence the discourse about this topic, even within the scientific community.

So you may be pretty sure that the "big questions" with implications for policymaking - e.g. "is it beneficial to regulate CO2?" or "are all statistically observed cognitive differences between groups caused by discrimination?" - are answered by the herd mentality ("Yes", "Yes"), not by serious scholarship that is only allowed for (politically) "smaller" questions. And all such questions end up on the left side because virtually everyone in the current Academia is "progressive" (and the conservative exceptions are mostly sissies). It wasn't always like that: in Germany of the 1930s, there was, on the contrary, a right-wing bias in science (at least with a certain definition of the political right) which was, of course, at least as bad as the contemporary bias. But this bias doesn't mean that all disciplines are equally contaminated by this junk and that you must throw all of science away.

When you look at more abstract disciplines (such as black hole physics), the direct links with politics largely disappear. It doesn't mean that the amount of groupthink is exactly zero. But if there is some groupthink somewhere, it is always local and other groups and cultures can compete with it - and a competition of different groupthinks is sufficient for objective science to continue.

It is simply not true that every individual scientist should be thinking (and can be thinking) about every single question completely independently. Because of their finite capacity, scientists have to rely (and do rely) on some "relatively trustworthy" sources that they identify. When it turns out that they shouldn't have (because the predictions were falsified), they modify the strategy and adjust the weights. And in many cases, it is also useful for (relatively) leading scientists to have some "junior colleagues" who buy the "big picture" from their bosses and who help them with hard work, especially if they know that the bosses are smarter and more experienced: not everyone is another Isaac Newton even though it is fashionable and politically correct to claim otherwise these days (billions of stupid people simply love to hear that they're at least as good as Isaac Newton).

As long as some scientists, at least the (relatively) leading ones, have the freedom to modify their scientific strategies, there is no problem to talk about here. Every attempt to social-engineer a different level of independence of the individual scientists is counter-productive because a large part of scientists are "natural mavericks" and the "market of ideas" determines the ideal balance between the independence (and mavericks) on one side and collaboration (and team workers) on the other side. If there are teams that are too unified or too fragmented, they will statistically lose to the more optimal ones. And if they don't lose, it simply means that the degree of unity doesn't matter. The same scientific results may be found both by individuals as well as by teams.

If a group of scientists largely relies on rational, individual, reproducible, unemotional, scientific arguments and quality scholarship in general, it is likely that it will win over another group spoiled by groupthink. Why? Because science simply works. The better group will eventually find better theories and evidence and arguments that will dissolve and transform the beliefs of the competing groups. They will gradually convince others - because not everyone in the competing groups is a completely dishonest and silly zealot (that's one of my assumptions here).

The only possible dangerous exception where the assumption breaks down occurs when no scholars have any chance to leave the groupthink because the groupthink is global in character. For example, if you must be afraid to say that a politician who is a scientific crackpot is a scientific crackpot - just because almost everyone else has voted for him as a politician in 2000 and they put politics above science - then the system is in real trouble. The same problems occurred in the era of the Inquisition when the Church (temporarily) had similar tools to globally control certain important segments of science. But whenever there is a scholarly place in your country or in the world where you can realistically escape from the groupthink, things are OK.

The topics related to the "equality of people" and "regulation of the evil markets" are perhaps the only topics that are plagued by a universal groupthink induced by a global bias in the scholars' opinions - a bias that is driven by obvious personal interests (e.g., the people in the Academia typically want the government redistribution to be high because they're mostly paid from the taxes). It might be a good idea to do something about these sick, politicized disciplines. But one must be careful not to throw the baby out with the bath water.

And that's the memo.

A new kind of mirror symmetry

Hep-th papers on Monday

Among the 17 papers that appeared on hep-th today, a majority is about stringy topics. Thank God, things are not getting crazy.

Cvetic and Weigan design a a new "canonical" type of gauge-mediated supersymmetry breaking with an anomalous U(1) and its realization in terms of D-braneworlds in type I string theory. Predictions of superpartner masses, plus minus an order of magnitude, are included.

Joseph and Rajeev identify a (not quite) new classical limit of string theory - at very high densities (string gas cosmology) - and describe its main observables in the Hamiltonian formalism.

McLoughlin and Roiban combined the membrane minirevolution with the Penrose/BMN limit of the AdS4/CFT3 correspondence. Their BMN-like analysis of dimensions of operators in the new N=6 Chern-Simons theory disagrees with some predictions recently made using the Bethe equations.

Bedoya studies the pure spinor formulation of superstring theory at the one-loop level. The one-loop corrections to the nilpotency of Q can be used to calculate Chern-Simons corrections to the Yang-Mills low-energy limit.

Sun discusses the flat directions in supersymmetric theories. They don't exist for generic Kähler potentials in supergravity but when you decouple gravity and simplify the potentials, to end up with global supersymmetry, flat directions often occur. He discusses the stabilized vacua in the middle and the qualitative nature of this interpolation between SUGRA and global SUSY.

Kazama writes down the superstring dynamics in backgrounds with RR-fluxes in the semi-light-cone gauge, clarifying the relationship with the normal light cone gauge (a description we know from the BMN limit).

Aschieri, Ferrara, and Zumino offer an interesting philosophical review of electromagnetic duality or S-duality in four dimensions: the group structure, special features in the supergravity context, and basics of Seiberg-Witten-like theory for the N=2 theories where special Kähler geometry is important.

Klusoň generalizes a procedure to derive the D2-brane action from the M2-brane theory, in the membrane minirevolution, to the more general non-linear case where you don't go to low energies - the Dirac-Born-Infeld action. The first preprint number in his abstract is clearly incorrect. I find the DBI picture of many branes controversial even in the case of D-branes, not only M-branes, but I hope that Josef mostly knows what he is doing.

Kodama, Kokubu, and Sawado study the Einstein-Skyrme model - general relativity with extra scalar fields whose configuration space has a non-trivial homotopy group so that one can "wrap" spacetime configurations on the theory's configuration space. They write down some brane solutions to this theory and discuss its excitations, especially the fermionic ones, with a focus on their masses.

Catelin-Jullien, Faraggi, Kounnas, and Rizos wrote a new paper about their new kind of mirror symmetry for heterotic strings. I believe it's the best paper today and I will talk about it at the end.

Magnen, Rivasseau, and Tanasa look at limits of non-commutative field theories. These theories tend to have a better ultraviolet behavior and may be unexpectedly renormalizable, as a result of the noncommutativity. However, the commutative limit on a "classical geometry" is naively nonrenormalizable. They argue that they have a way to take the limit so that the limit is renormalizable. I have some serious doubts whether it's possible and whether the limit is "more canonical" than other regularizations of the same nonrenormalizable (commutative) theories but I haven't read the whole paper.

Brandhuber, Heslop, and Travaglini discuss a topic that was also covered in several recent papers: the dual superconformal transformations of the N=4 gauge theory, the most famous AdS/CFT example. Very recently, Drummond et al., as well as Berkovits and Maldacena, pointed out a new kind of "fermionic" T-duality in the non-linear sigma model describing the string worldsheet in the AdS5 x S5 background. Once you do this transformation, you end up with an identical model but the original strongly coupled amplitudes can be mapped into a calculation of some specially engineered Wilson loops in the dual theory. The present authors prove the dual superconformal symmetry of the S-matrix of the original (or final) theory.

Billo', Ferro, Frau, Fucito, Lerda, Morales find a lot of D-terms and F-terms in type IIB orbifold flux vacua generated by mostly fractional D-brane instantons.

Rosten links the asymptotic safety of the Wess-Zumino model to the existence of a certain fixed point (with an operator whose anomalous dimension is negative; and with a certain direction keeping some properties of the Kähler potential) using Pohlmeyer's methods and nonrenormalization theorems.

Lalak and Eyton-Williams look at supersymmetry breaking from another angle. They take the Intriligator-Seiberg-Shih model (no, ISS is not the International Space Station in this case), assume a dynamical cancellation of the cosmological constant, generate F-terms of some special type, and conclude that in this gauge-mediated setup, soft scalar masses are about 100 times heavier than gauginos and friends.

Gurau, Magnen, Rivasseau propose their new replacement for both Feynman path integrals as well as Feynman diagrams. In their new framework, only tree Feynman-like diagrams occur. And loops and divergences disappear. ;-) Well, I wouldn't really bet that this paper is correct. Quite on the contrary. Some people are obsessed with the elimination of divergences but they forget that physics is supposed to calculate physical phenomena. I assure similar authors that in the hypothetical case that something like their approach is possible, the first acceptable paper about it will quantitatively re-calculate a well-established quantum (loop) process using the new formalism, rather than just claim, using a lot of Garrett Lisi-like formal nonsense, that a new fantastic gadget exists.

Carlip derives the number of propagating degrees of freedom (one) and dimensions of the boundary CFT operators in topologically massive AdS3/CFT2 by choosing new degrees of freedom in the bulk that simplify the constraint algebra. At least he claims so. ;-)

Spinor-vector duality in heterotic vacua

I chose the paper by Tristan Catelin-Jullien, Alon E. Faraggi, Costas Kounnas, John Rizos to be my daily winner.

They look at the free-fermionic heterotic vacua, favorite models of your humble correspondent from the early 1990s. Most of my computer passwords used to be encoding a short version of the phrase "free-fermionic 4-dimensional heterotic vacua". ;-)

In these models, the 16 "excessive" left-moving bosons on the heterotic worldsheet are fermionized (into 2 fermions per boson, as always), much like the hidden 6 dimensions, leading to a theory with four X_m(sigma,tau) and 32+12 + 8+12=64 fermions in total (counting the light-cone gauge physical degrees of freedom only). A lot of GSO projections (and twisted sectors) acting on subsets of these 64 fermions are postulated.

The resulting spectrum naturally resembles the MSSM/GUT supersymmetric vacua. It is believed that most (or all) of these models describe special points of the moduli spaces of normal heterotic compactifications on Calabi-Yaus, usually orbifold points. But in these particular free-fermionic models, it is very natural for the number of generations to be three.

They have classified large sets of these models and found something that is very reminiscent of mirror symmetry.

If you choose the GUT models with the SO(10) gauge group, you may count the number "V" of the vectorial "10" representations and the number "S" of the spinorial "16" representations of the gauge group. It turns out that for every model with the numbers (V,S), there also exists a model with the numbers (S,V).

These two models are inequivalent at low energies, at least they look so. So it is analogous to type IIA on a Calabi-Yau X and type IIA on a Calabi-Yau Y which is its mirror (the latter is equivalent to type IIB on X): two non-equivalent models. Even in the mirror symmetry case, I don't know a direct physical relationship between "type IIA on X" and "type IIA on Y" except for bookkeeping. So their comments about "topology change" and "different low-energy manifestations of the same high-energy physics" could be more speculative than they think: haven't they forgotten that the two members of their pairs are inequivalent theories?

The models with "S=V" are kind of self-dual (analogous to self-mirror) and they restore some symmetry. In the type II case of mirror symmetry, you would naturally get the same number of vector multiplets and hypermultiplets, expecting some enhanced symmetry (especially supersymmetry), for example if you pick the Calabi-Yau to be a K3 times a two-torus in order to double the number of supercharges.

Analogously, in the present heterotic setup, the S=V case is special. These vacua normally restore the E6 gauge group. Recall that the fundamental representation of E6 is decomposed under the SO(10) subgroup as 16+10+1, giving you the same number of the vectorial and spinorial representations.

At any rate, this is a new pairing between vacua, one that is proven in the new paper. It seems that there are many more similar relationships between string vacua than what we thought. The set of all vacua resembles a brain where every neuron is connected to many other neurons by many synapses.

If you think that a brain is too artificial, then you are probably one of those dumb creationists from Not Even Wrong (such as Roger Schlafly) whom I tried to completely eliminate from this blog. In case I failed in my difficult elimination task, let me boldly inform you that the brain has evolved naturally, too. ;-) The relationships between the vacua in string theory are governed by pure maths that works everywhere, not only in our Universe, and there is consequently nothing artificial or arbitrary about such relationships and nothing artificial or arbitrary about the landscape.

One (or your humble correspondent) could also speculate that these insights are important for the vacuum selection problem. For example, Nature could be naturally preferring vacua that are very close to various symmetries - with small (but nonzero) differences between "S" and "V", among other things.

At any rate, these new relationships should be studied. It should be determined whether the mysterious link between the pairs of vacua has a meaning beyond the perturbative series. The relationship should be interpreted in as many ways as possible and whatever we're doing in the mirror symmetry case should be tried in this case, too.

And that's the memo.

Loránd Eötvös: 160th birthday

Baron Loránd von Eötvös was born in Buda into an aristocratic family connected with Vásárosnamény, Hungary - a town near Ukraine - 160 years ago, on July 27th, 1848.

Fortunately, Lóránd wrote both in Hungarian and German which is why most of the world can learn about his results (and forget about his full Hungarian name, Vásárosnaményi Báro Eötvös Lóránd). He focused on surface tension of liquids and gravity.

His father József was a statesman, educator, and novelist who was also a friend with Franz Liszt, the composer. When Lóránd was born, his father was a minister in the 1848 revolutionary government for a while. Gusztáv Keleti, a painter, was chosen as Lóránd's tutor, and the young future physicist turned out to be real good in drawing (especially on his trips) and poetry. Later, he became one of Europe's best mountaineers (and took a lot of photographs on his trips). He has also climbed a few peaks in the Dolomites so that one of them (in the middle of the picture below) is even named after him!



He wasn't bad. But let's return to his youth.

He studied many subjects at school. His interest in maths and physics clashed with the family tradition. So he entered the University of Pest in 1865 to study the law and become a politician. (The city was merged with Buda into Budapest in 1872.) Lóránd was taking private math lessons from Otto Petzval. His father accepted that it was science, not the law, that his son should pursue.

Lóránd worked in a chemistry lab before he moved to Heidelberg in 1867 (under Kirchhoff who taught him to make accurate measurements and Helmholtz who showed him the power of personal discussions - and others) where police cautioned him just because he was loudly singing on the street with his friends! :-)

Incidentally, the current students of the Eötvös Loránd University clearly follow his example.

After some time in Königsberg (where Franz Neumann taught him a lot about potentials and theoretical physics in general), he received a PhD in Heidelberg in 1870 (the thesis was about Fizeau's problems, one of the early steps that helped special relativity).

Once his dad died in 1871, he returned to Hungary and inherited the dad's title and a chair in the upper house of the Hungarian Parliament in 1872. In politics, he would later do some things related to education and research - for example, he founded the Mathematical and Physical Society, later named after him. But let's return to 1871. Lóránd instantly became a privatdozent of theoretical physics and added experimental physics a few years later. He married Gizella Horváth, a politician's daughter and a skillful pianist with a cool handwriting who spoke French well. Their daughters - see/click the picture on the left - became celebrities as athletes.

He returned to the problem of surface tension (from his student years in Königsberg) in 1876 and spent a decade with it. He measured it accurately and showed that its temperature dependence is universal for all liquids (Eötvös rule):

SurfaceTension x MolarVolume^2/3 = EötvösConst x (TemperatureCritical - Temperature)

In 1886, he fully focused on gravity which was his big scientific topic until the end of his life in 1919. And of course, he is most famous for his experiments that I will discuss in the rest of this text:

Torsion balance experiments

How did he begin to study this problem? Well, the University of Göttingen offered a prize for someone who would improve the experiments initiated by Galileo that show that the acceleration in the gravitational field is universal for all materials. And Lóránd was the right one to recycle and update the design of Henry Cavendish's experiment from the late 18th century and to improve the accuracy behind the weak equivalence principle to 5 parts per billion, much better than what Newton and Bessel have achieved previously.

In the Eötvös experiment, two different masses are attached to the ends of a horizontal rod, hung from a thin string. The rotation of the rod is monitored by looking at a mirror attached to the rod (or string) through a telescope.



If the inertial and gravitational masses were different, the Earth's gravitational acceleration (proportional to the gravitational masses) would act on the masses differently than the centrifugal "radius times omega squared" force from the Earth's spin (proportional to the inertial masses). I assume that I can afford a simple jargon because you know how to calculate these things and I don't have to introduce more accurate concepts such as the "centripetal force". This mismatch would make the rod rotate which could be seen pretty well through the telescope.

Of course no mismatch of this sort has ever been measured - even though the experimenters in the 21st century such as those in the Eot-Wash group in the Washington state are almost 1 million times more accurate than their old Hungarian colleagues.

Consequences

The weak equivalence principle demonstrated by this experiment is, of course, one of the key principles behind the general theory of relativity. General relativity satisfies this principle: it was, in fact, historically constructed by Einstein who assumed this principle once he appreciated its strength. Newton's theory agreed with this principle by choice. However, unlike general relativity, it didn't explain the principle because one could have written down a similar theory where the masses are different.

This old-fashioned, classical principle is a huge problem for all speculative physicists who try to invent a theory of "emergent" gravity where the gravitational force results from something else than the curvature of space and time - such as new kinds of superconductivity. If you can't find a reason why the description of gravity at long distances in your theory is going to be exactly equivalent to the curved spacetime as envisioned by general relativity, it is pretty much guaranteed that your theory doesn't satisfy the principle exactly.

The probability that your theory satisfies the principle approximately and it is compatible with the experimental bounds on the violation of the principle is equal to 10^{-16} or less, a number related to the accuracy of the experimental tests of the equivalence principle. If there's no good reason for the double ratio of inertial and gravitational masses of protons and neutrons to be equal to one, a generic theory is going to predict this double ratio to be a "random number different from one". And the probability that such a random number differs from one by less than 10^{-16} is comparable to 10^{-16}. Different materials, with different proportions of protons and neutrons, will respond differently and twist the torsion gadget.

In other words, people like Robert Laughlin are pretty much screwed.

How does it work in string theory? In perturbative string theory, you may derive gravity through the interactions caused by the exchange of gravitons which are closed strings in a particular vibrational state. At the beginning, you don't see any equivalence principle over here and you might be afraid that string theory is going to follow the fate of Laughlin's or Smolin's theories of gravity and go glub, glub, glub to the bottom of the sea before they even get a chance to put them out there. ;-)

However, when you study the theory more carefully, you will be able to prove that the presence of an additional graviton - a particular closed string - in any particular scattering process has an indistinguishable physical impact from a modification of the background geometry where all the strings propagate: see

Why string theory includes gravity

More precisely, the amplitudes in the original - e.g. flat - space including additional gravitons are equal to the derivatives of the amplitudes without the graviton in a general curved space, differentiated with respect to the curvature and evaluated at the original geometry. The amplitudes of particles not including gravitons at arbitrary curved backgrounds are the generating functionals for all amplitudes at a chosen background with an arbitrary number of gravitons. These words are probably useless if you don't know the formulae, anyway.

At any rate, the equivalence principle is exactly satisfied by string theory even though some descriptions of string theory are able to obscure the reasons and make the principle look like a miracle to a physicist who hasn't studied physics of the theory intensely enough. But if the reasons behind a feature of a theory are obscured, it is just the theorist's potential problem or a complication: it is not a problem of the theory itself. What matters for the fate of a theory is whether its propositions are true, as checked by observations, not whether they are easy to see. And for string theory, it is the case: its predictions related to the equivalence principle are right.

Matrix theory and AdS/CFT obscure the reasons, too. These two approaches don't even allow you to start with a general curved background, at least not in a simple way. Also, you can see the physical polarizations of the gravitons only: the pure gauge polarizations are absent from the scratch. However, one can still prove that all the general facts about gravity that normally follow from general relativity are exactly satisfied because these theories - e.g. Matrix theory and AdS/CFT - can be shown to be exactly equivalent to other descriptions where the equivalence principle is manifest.

So if a theory has any chance to describe gravity as we know it today, the metric tensor must be demonstrably present in its low-energy limit and it must be possible to see that other kinds of matter depend on this metric tensor in the same way as they depend in general relativity. Because the metric tensor without anything else can't lead to finite amplitudes at higher energies, we also need some additional players in the story.

The physical phenomena and backgrounds connected in the rich network that we continue to call string theory are the only mathematically possible quantum solutions to the combined problem of finiteness and equivalence principle. It's the only framework where the curved geometry is sufficiently emergent to tame the infinities and to tell us about the inner nature of the force but also sufficiently manifest to agree with the equivalence principle as tested by the experiments initiated by this Hungarian nobleman.

And that's the memo.

Cargo cult science: a video

Many of us love Richard Feymman's 1974 commencement speech about cargo cult sciences, disciplines that seemingly seem to follow the scientific method but something must be wrong because no airplanes land.

Feynman was trying to explain what's wrong with various careless, agenda-driven, biased, preconceived mental frameworks that try to pretend that they are scientific but they don't honestly eliminate falsified hypotheses according to the results of objective tests. Feynman also predicted the global warming pseudoscience and warned scientists against being abused by the politicians:

I say that's also important in giving certain types of government advice. Supposing a senator asked you for advice about whether drilling a hole should be done in his state; and you decide it would be better in some other state. If you don't publish such a result, it seems to me you're not giving scientific advice. You're being used. If your answer happens to come out in the direction the government or the politicians like, they can use it as an argument in their favor; if it comes out the other way, they don't publish at all. That's not giving scientific advice.

Just replace "drilling a hole in the state" by "regulating carbon dioxide emissions" and you will see a very urgent warning by Feynman for our contemporaries.

But have you ever seen the details of the prototype cargo cult science? I find this social phenomenon rather amazing.



Video 1: From Mondo Cane, an Italian documentary (1962)

Go to 4:50 of this video for another footage of the cult.

What are you waiting for? Women making up 50% of Fields medal winners because someone thinks it would be nice and natural for women to be equally stellar mathematicians as men? Eggs that are both breaking and unbreaking because it would be nice to restore the time-reversal symmetry in the macroscopic world? Or are you looking for a stable, permanently happy, and flat Earth's climate without any variations that will follow the ban on sinful SUVs? Are you waiting for loop quantum gravity to make manifestly cutoff-dependent objects finite and unique?

If you do, see the video above to understand how you approximately look like from my reference frame.

Bonus

Rush Limbaugh, one of the most effective preachers in the world, tells you to prepare for the Large Hadron Collider. Write your will etc. Very funny. ;-) My understanding is that Rush wants to humiliate the warming alarmists and he views the LHC alarmists as even more ludicrous than the warming alarmists. But if Rush intended to be serious about the threat, it is even more funny! ;-)

The Sun seen to repeat the Dalton minimum

David Archibald's analysis (click)

of the length of various solar cycles seems to indicate that right now, at the end of the (very long, perhaps 13.6 years, it's not yet really over) solar cycle 23, we seem to be in a similar situation as we were after the long solar cycle 4 (13.6 years). Both of them were preceded by very short cycles (SC3: 9.2 years, SC22: 9.6 years).

See the sun spot number charts

The following solar cycle 5 at the beginning of the 19th century could therefore be mimicked by the imminent solar cycle 24. It had an anomalously long period of rise (6.9 years) and a short period of decline (5.4). Usually it is the other way around (4 years vs 7 years in average). The solar cycle 5 was the first half of the Dalton minimum (1800-1825 plus a decade before and five years after these two cycles) that was correlated with (and maybe brought) a period a cooling.

Janet Hyde: boys = girls in math? Not really

Hundreds of media outlets - including the New York Times whose Tamar Lewin mentions Lawrence Summers in the very first sentence - uncritically report that "girls are equally good as boys" in math. This highly surprising statement is claimed to be based on a paper in Science magazine.

Janet Hyde et al.: Gender similarities characterize math performance

Janet Hyde herself, a self-described feminist psychologist, seems to be a prototypical 2nd wave feminist, too (click her picture or check her publication record). She thinks that "her biggest contribution to feminist sexology is her college sexuality textbook" (exact quote). She believes that the supposed higher rate of masturbation among boys and men has "enormous implications" which, she believes, was her second "major contribution" to feminist sexology. This difference between sexes goes in the "right" direction so these "scientists" choose to believe it and promote it. We can finally appreciate her third "major contribution". ;-)

All five co-authors are women who have been writing similar cargo cult scientific papers for quite some time.

It is enough to read a brief review in Science to see that the headlines don't follow from the paper at all. The review explains the main reason of the results: they have detected no signal because the tests were too simple. They didn't really test "g" or the ability to think mathematically but rather attainment. And the standards are dropping. David Malakoff writes:

The study's most disturbing finding, the authors say, is that neither boys nor girls get many tough math questions on state tests now required to measure a school district's progress under the 2002 federal No Child Left Behind law. Using a four-level rating scale, with level one being easiest, the authors said that they found no challenging level-three [strategic thinking] or [level]-four [extended thinking] questions on most state tests. The authors worry that means that teachers may start dropping harder math from their curriculums, because "more teachers are gearing their instruction to the test."

That's what the media should actually worry about - decreasing quality of American kids' math skills - but no one does. It's just too bad if there are no challenging problems. The tests they have processed had nothing to do with strategic thinking and extended thinking. It wasn't really about the math that matters in math-loaded occupations.

The last sentence says:

Among students she's observed, she says "the boys tend to be a little more idiosyncratic in solving problems, the girls more conservative in following what they've been taught."

Yes, that matches my experience, too. The latter approach is normally called "a lack (or shortage) of creativity." If you combine this observation about boys and girls with the statement that "more teachers are gearing their instruction to the test", you may guess whether it is the boys or the girls whose scores will be raised.

Check e.g. California's standardized math test for grade 7 to see how low-brow and mechanical these tests are.

Newspaper articles build their far-reaching statements on grades 2 through 11. The paper by Hyde et al. however did find that boys have an edge in the SAT tests before they enter the college. Hyde herself offers a conceivable but not straightforward interpretation of this fact - one that she chose not to apply in other cases. For a certain reason, this portion of the paper - which is much more important for our understanding of the development of the math talents - is not being reported or, to say the least, it doesn't influence the headlines.

The magnitude of variations

Most importantly, those five co-authors don't seem to discuss the variance of the distributions in the media. The larger second moment of the male distribution is what primarily decides about the small percentage of women in math-loaded occupations (especially the top ones), more than the central value does: see detailed calculations by La Griffe du Lion. Before those five spice girls made their bombshell statements about girls matching boys, they should have made sure that they could match boys (such as Rushton and Nymborg) in mathematics themselves. ;-)

Not to be unfair, their paper does mention that in the 99th percentile, they found the boys:girls ratio to be 2.06:1 (and for the 95th percentile, it was 1.45:1). Incidentally, these numbers roughly agree with Figure 2 in La Griffe du Lion's text about these matters. But Hyde et al. were very careful that this particular result didn't get into the media.

National Post (Canada) explains that these findings of the paper about the variations support e.g. Lawrence Summers' statements...

In the paper, they also say some "likable" stuff about the ratio being different for Asians: some people argue that this shows "complex cultural factors". That's of course complete rubbish. The ratio is closer to one for Asians simply because the Asian boys and girls have a higher central value, and the 99th percentile of the whole society therefore cuts their distributions closer to the bulk where the difference in variances doesn't play such a role.

Even if this effect were not enough to explain all the data, one should realize one more obvious thing: there is no reason why the magnitude of math skills gap between the sexes should be exactly universal for all races. Of course that different races have different innate aptitudes for maths and they can also have different differences between the sexes. This would show that the biological factors are more important, not less. In the (highly selective) case of the mathematical Olympiad discussed below, boys have a significant edge among the Asian nations, too.

It's been more than three years when Larry Summers introduced the width of the statistical distributions into the public debate but when you make a Google search, you will see that 99% of people still don't seem to get the point. Most people in the world are just stunningly stupid.

If you're one of them and you're disturbed by all these differences and you want to hear something encouraging about ordinary people, let me tell you that it can be calculated that if you pick a random man and a random woman, the woman will be g-smarter than the man in 45% of the cases. You need to calculate a somewhat tough integral to get this result. As Barbie correctly said, math class is tough. ;-)

Mathematical Olympiads

The girls tell us that the gap is now gone and everything is equal. The only problem is that no airplanes land and the percentage of girls in math-loaded occupations stays comparable to 10% or so and among the Fields medal winners, it is 0.0%.

In order to show you a much more meaningful and transparent measure of the real mathematical talent among American boys and girls, let us look at the winners of the U.S. Mathematical Olympiad. Every year, twelve winners are officially announced. We will start with the year 2007.



Click the picture to zoom in and read more about the 2007 ceremony (click). The guy on the left in an official and the remaining 12 high school seniors are the winners. The young lady in the light blue dress on the right side is the only female winner. Congratulations! She happens to be of East Asian descent. The East Asian people happen to have a higher IQ by about 10 points than the Caucasian people. At least, the PC people could be thrilled about one black guy kneeling in the middle. (Oops, it turns out that he is actually an Indian American, would you believe?) I am thrilled, too - and so am I by the remaining 11 winners.

But let's forget about geography for a while.

If the probabilities that girls and boys become winners were equal, the probability that there will be less than 2 female winners would be equal to 13/4096 = 0.003. That's approximately one part in 300. But yes, you might still say that it is a coincidence. Moreover, 2007 is not the most recent year. Why doesn't Mr Motl look at the 2008 ceremony (click)? It must have been an inconvenient one, right? Well, here it is.



Click the picture to zoom in. The background is a bit more complicated now :-) - there is one Einstein and 2+2 old officials at the bottom side of the picture. Nevertheless, there is not a single girl here. (There is no longer any guy who looks black here either, but we don't want to analyze geography in this text.) If you assume the 50:50 probability for them to become winners, the probability that there is no female winner equals 1/4096 = 0.000024.

Finally, you can combine the two sets of winners. If you assume that the a priori chances are 50:50, the probability that among 24 winners, there would be less than 2 female winners is equal to 25/2^24 = 0.0000015, roughly one part per million. That's already pretty much a five-sigma falsification of your hypothesis about "equality". Moreover, all these kids have spent all their lives in the atmosphere of political correctness so one would have to be really mad to argue that the small percentage of girls is due to the terror against female scientists. ;-)

At this moment, the egalitarian people have to claim that all the organizers of math Olympiads, including the old lady (Mary McKay) on the 2008 photograph, are despicable sexist pigs.

But because this result is so perfectly reproducible, I could add as many teams as I wanted, reducing the probability that such a thing can occur by chance virtually to zero. For example, among hundreds of known names of Czechoslovak participants of the International Math Olympiad (which I kind of screwed back in 1992, unlike the national level), you only find four female names: the probability is of order 1/2^200 = 10^{-60}. Analogously, there are 4 girls in the 1993-2008 list of the 96 Czech Republic participants, below 5 percent. (Feel free to check other countries.)

(Ms Jana Syrovátková whom I know very well earned a gold medal in 1993 which was amazing. If you care about these things, the last 1992 Czechoslovak team where I competed was the 13rd country which was one of the worst results in history. ;-) On the other hand, the 10th place of the first 1993 Czech team was fine; Slovakia was 12th in 1993. However, after 1993, both Czechia and Slovakia were always much worse than we were in 1992 and recently our teams are both around the 35th place in average. We simply can't compare to Hungary or Romania and I am not sure about the exact reason.)

But whether you like to hear it or not, the idea that there is as much math talent - and I am talking about the higher end - among high school boys and high school girls is utterly absurd. In the fast comments, additional statistics about the International Mathematical Olympiads are discussed. For example, the female percentage in the teams (10% in average in 2008) is heavily correlated with the success of the team. The winning teams are near 1% while the losing teams at the bottom approach up to 30% of girls.

This correlation can't be explained by any bias in education "before the olympiad": you would have to accuse the IMO graders of fraud. Instead, this correlation proves that the average global cutoff for the girls to attend IMO was somewhat lower. Despite this fact, the girls only made up 10% of the participants.

And the significant gap is not dropping in any sense - the two pictures above would indicate just the opposite trend but such a conclusion wouldn't be statistically significant. What may be dropping is the quality of the generic math education in the U.S. which is the thing that the journalists should worry about. But because most of them hate maths anyway, they prefer to focus on (and twist) different things.

The rate of female physics/chemistry Nobel prize winners has dropped, too (there's been none since the early 1960s), for exactly the opposite reason. Relatively speaking, it becomes tougher to earn a Nobel prize "by chance" (sorry, Marie Curie!). This fact doesn't mean that the new discoveries are more revolutionary than the old ones. On the contrary, they may be less revolutionary but they require a lot of systematic high-expertise work. Quite clearly, the more selective your math-related tests become, the lower percentage of females you will obtain (the boys have a greater variance of the distribution).

The high school math Olympiads are more selective than tests accepting undergraduates to colleges but less selective than Nobel prizes. The silly mechanical tests underlying the paper by Hyde et al. are not really selective and if you score well, it doesn't mean that you can do math-loaded things. It only shows that as a child, you were not quite left behind. ;-)

PC = -IQ

Incidentally, another new study found the political correctness of disciplines to be a highly decreasing function of their IQ. The dumber you are, the more politically correct you are. For example, as far as PC goes,

Psychology > Sociology > History > Political science > Biology > Mechanical engineering > Electrical engineering

As far as IQ goes, these disciplines are sorted exactly in the opposite order. Check the previous two links! ;-)

Click the IQ sticker below to see more articles about innate aptitudes and related stuff.

Google Knol

We didn't know but it turns out that knowledge has two units, "knol" and "edge". Edge.org has been registered by John Brockman's foundation for quite some time but

Knol.google.com (click!),

Google's competitor to Wikipedia and/or an alternative arena for formal encyclopedic blog articles (with reviewers, collaborators, and AdSense payments to authors), was just launched. A Google account is required for you to contribute.

(Yes, the Google guys have screwed the W.)

Share what you know Write a Knol (click!)

More information: Google blog Blogger buzz Google news

Spontaneous symmetry breaking & society

Sean Carroll is promoting a new analogy between the concept of spontaneous symmetry breaking in physics and various phenomena in the society.

I think that the analogy sounds silly but it is actually much better than he realizes, as long as you concentrate. We will look at it somewhat carefully and I will argue that the paradigm of spontaneous symmetry breaking shows why most left-wing people and social engineers, including Carroll himself, completely misunderstand what the rule of law in a democratic country means and what it doesn't mean.

Let me say in advance that the basic principle of spontaneous symmetry breaking, namely that

the symmetry is broken at long distances but restored at short distances,

is turned upside down by Carroll. This principle is very important both in physics and in the democratic society. Carroll is like a student who could memorize the term "spontaneous symmetry breaking" but he hasn't learned or understood its basic properties. F.

Physics: unification at short distances

Let me start with physics. Neutrinos and electrons look very different in our everyday world. Electrons are heavy and interact electromagnetically; neutrinos are light and their interactions are negligible.

However, it turns out that when you increase the energy of all particles to hundreds of GeV per particle or higher or - equivalently - if you study experiments to reveal the architecture of matter at distances comparable to 10^{-18} meters or shorter, you will discover something called the electroweak unification.

The properties of (left-handed) electrons and (left-handed) neutrinos will become indistinguishable. All of their interactions with the rest of the world will have the same probabilities, assuming that you replace the other particles in every process by their electroweak partners, too.

In the world of short-distance phenomena, the symmetry holds. But the Higgs boson in the Mexican hat potential makes the symmetry disappear in the long-distance phenomena. That's why photons are massless but W,Z bosons are not. That's why the electrons interact differently than the neutrinos.

Another example is the chiral symmetry breaking. At short distances, the left-handed and right-handed portions of the quarks carry two independent (approximate but almost exact) color symmetries. But at distances longer than the proton radius (QCD scale), the left-handed and right-handed components must combine into a Dirac spinor and only the "overall" SU(3) symmetry rotating them simultaneously survives.

There may exist many similar symmetries that are broken at long distances but they haven't been empirically established so far. Supersymmetry might be restored at distances shorter than something like 10^{-19} meters or less while a grand unified symmetry, extending the democracy between electrons and neutrinos to the quarks (and generalizing the SU(3) symmetry between colors of quarks from the previous paragraph that is never broken in our world), might take over at distances shorter than 10^{-32} meters.

But there also exist simpler examples outside high-energy physics. For example, materials can be found in different states of matter. H₂O can be a gas (vapor), liquid (water), or solid (ice). At very short distances, you may find out that all these seemingly different materials are made out of the same H₂O molecules: that's why you can easily change ice into water or vapor and vice versa.

When you focus on the state of matter that corresponds to low temperatures - which are also related to low energies and long distances - it is nothing else than the ice. Ice is a crystalline solid. Liquids or gases are invariant under rotations: for example, a symmetric glass of water doesn't change if you rotate it by a nonzero angle.

However, this rotational symmetry is broken by crystalline solids such as ice that pick preferred directions in space. This symmetry breaking only occurs at long distances - when you can actually see sufficiently many molecules to figure out that they like to organize themselves into a crystalline structure. But you couldn't determine that the symmetry is going to be broken by looking at a few molecules in your microscope only.

Society: equal rights of individuals

What does Sean Carroll mean by the symmetry breaking in the society? Well, he proposes that the blacks should have human rights that other groups don't have. For example, the blacks should be allowed to say "nig*er" while the whites shouldn't. But he would clearly like to extend his "symmetry breaking" to many other situations in our lives, too. One of his other proposals is that quality control shouldn't quite apply to women in science. He justifies this unusually unequal treatment of the individuals by his desire to equally treat the groups overall.

The examples from physics that we mentioned above should make it instantly obvious that this is exactly how symmetry breaking in physics doesn't work. Carroll's policies are also profoundly incompatible with the very basic rule of law in a democratic society.

In a democratic society, it is the individuals who are guaranteed equal rights and equal opportunities, if you wish. This rule is directly analogous to the restoration of symmetries at very short distances. The national and even international laws treat them - or should treat them - equally. But what these individuals do with these rights depends on where they live, whom they interact with, what they are able to do, what they like to do, and what they decide to be. The outcomes will inevitably be different.

In the example involving the states of matter, every H₂O molecule had the same "rights": it had to follow the same local laws of physics. Nevertheless, the macroscopic conglomerates of these molecules sometimes looked like a liquid and sometimes they became a crystalline solid. That's quite normal. That's how the symmetry breaking always works in physics.

Analogously, every democratic country guarantees the same rights to all individuals but they may lead to very different outcomes for different groups. It is quite normal - and, in fact, essential for a working society - that different groups end up using their rights and lives differently, depending on their traditions, abilities, and other innate properties.

Sean Carroll's idea about symmetry breaking is very different. He postulates that all the matter in the world should look like a uniform material of a constant density in a particular state of matter - I guess it is some kind of a liquid, but surely not a drinkable one. But because it doesn't seem that this is what the molecules always wanted to do, he requires that the mass, size, and interactions of every molecule must be changed in such a way that his dream about the universal water - a material containing hydrogen atoms, nitrogen, argon, iron, gold, and strangelets living in peace with each other - is respected at long distances.

So the big government has to be given the tools to control the life of every individual atom and change his or her mass, size, and interactions with his or her family and neighbors as required for the society to look like Sean's universal water at long distances.

Sorry, Sean (and social engineers of all countries), but it is both non-democratic as well as impossible to create this universal water out of gold and nitrogen. Both at the level of the materials and the societies, this is not how the world works and any kind of a society that tries to do something crazy of this sort is guaranteed to end up as a totalitarian system that is fortunately going to collapse soon or later.

It's time for the far-left people to notice that there is something absolutely fundamental and critical about the society in particular - and the world in general - that they misunderstand or deliberately pretend to misunderstand.

And that's the memo.

Roy Spencer in the U.S. Senate

(See also Anthony Watts' comments.)

I think his testimony was extremely good. You can see the anonymous faces around who don't want to hear any rational things about the climate, its sensitivity, the natural effects, and the sensible strategies to organize the scientific research in order to find the correct and important insights about the climate.

When Spencer was finished, the only thing that Barbara Boxer was able to say was to congratulate that Spencer was jokingly named Rush Limbaugh's official climatologist. She just wanted to "point it out for people to understand". She apparently thinks that this comment should settle the debate. Well, among the [unflattering word] who vote for her, it probably does.



I have great news for you, Ms Boxer. You have been named the official clown of Rush Limbaugh's show which is a higher rank than the official climatologist. Congratulations! I hope that the next time, you won't be hiding your own title, either. :-)

150 minutes of video

A more complete video from the hearings is here. At the beginning, Boxer enumerates millions of catastrophes that are caused by warming, an effect that hasn't existed at least for ten years. As her following comments reveal, her support for this fashionable nonsense is mostly motivated by her desire to spit on Bush's administration. Mr Lautenberg blames global warming and George Bush for a disease of his grandkid: quite incredible. Testimonies and questions follow. You may also go to 1:01:40 where Frank Trautenberg or Lautenberg or what is the name of the old man (D - New Jersey) asks some questions to Spencer.

See also: a 30-minute scientific talk by Spencer

I must say that these arrogant political fools drive me up the wall and sometimes I must pause the video every 10 seconds to avoid overdosing. They don't know 1% of Spencer's knowledge about the climate but they still indicate that they don't have to listen.

Spencer says a lot of key things, for example that the humans obviously have some impact on the climate - for example, they influence the area of forests - which doesn't mean that they can stop using fossil fuels. Whether the carbon technologies can be replaced by something else in the future will depend on technological breakthroughs and you can't legislate new technologies into the existence. In fact, billions have already been spent and nothing that could be called a breakthrough has emerged.

But those political faces simply don't want to hear anything that makes sense. Instead, they want to tell Spencer and real scientists in general that they are putting children at risk. And they want to listen to bought scientists such as Kevin Trenberth to say things that the politicians pay them for saying. In his speech, Spencer recalls that Robert Watson, the 1997-2002 chairman of the IPCC, told Spencer 20 years ago that CO2 should be regulated (much like freons), years before a scientific "justification" was on the table.

It's a very sad tragicomedy - a great example how the active [unflattering word] such as Boxer and Lautenberg "naturally" get to the top of political affairs in every country that suddenly allows its government to decide about things that should only be decided by the free individuals. At this point, science is completely irrelevant. Science was only good in its manipulated, corrupt form to help the morons to get to their chairs and gain the power.

Frankly speaking, I found even comments by some Republicans, such as Larry Craig (around 56:00), who is a semi-skeptic, insulting, e.g. when he called Spencer "outsider" in the climate science. What the [intercourse] does it mean? By all objective criteria, Spencer is an achieved scientist at the center of his discipline.



Stephen Colbert with Sierra Club's Carl Pope - funny.

Incidentally, Antarctica was about 17 °C warmer 14 million years ago than it is today: ostracods have spoken.

Schellekens & anthropic principle

Albert N. Schellekens wrote a popular 87-page preprint,

The emperor's last clothes?

It is clearly a popular text but yes, indeed, it is way more technical than some books that are considered by their authors to be more-than-popular. ;-)



Wordle...

Schellekens, together with Dieter Lüst and Wolfgang Lerche, wrote a paper or two in the 1980s that argued that the number of vacua in string theory was huge, comparable to 10^{1500}. So if this insight is a discovery or a "paradigm shift", they should surely be included among the fathers of this idea. Well, I am not among those who would think that these "fathers" should be excessively proud about something or even fight for priority! :-) They just wrote a high number (an upper bound) whose derivation was not quite correct and whose philosophical consequences seem irrational to me (and at any rate, they were proposed centuries ago).

At the beginning, Schellekens criticizes the people who now say that they always knew that the number was huge but they didn't find it important enough to talk about it. ;-) Well, I think that his criticism is legitimate and I am not among the people criticized by Schellekens because I never thought that the number was that huge - even though now I think it is probably true - and I do think that this question is somewhat important: those who "knew" it shouldn't have been silent. But I also think that the large number of the vacua itself doesn't imply the anthropic reasoning.

So while there is a sense in which the anthropic principle is a very old story and no contemporary scientist should sell it as his discovery, it is also true that only the stringy flux compactifications that were found in this decade have made the possible anthropic picture of physics "complete". Even though string theory doesn't really imply that the anthropic reasoning is correct, it is also the only framework we know where the numerous vacua may be classified and co-exist in a huge multiverse. String theory offers the only satisfactory incarnation of the anthropic reasoning. As many other important keys, string theory is able to open the gates to the Heaven as well as the Hell.

Is uniqueness the same thing as anthropocentrism?

But as you can guess, I disagree with Schellekens' main theses. The anthropic principle is neither something we should be happy about (Schellekens views it as a victory of string theory and related breakthroughs) nor something we should feel certain about. However, this debate is not just about one-sentence "opinions" and even in his popular text, he has written 87 pages of somewhat insightful arguments. I won't offer you 87 pages but we will look at many of them, anyway.

First, there exist two full propaganda machines justifying the anthropic principle or, on the contrary, the possibility to find the full, unique, and complete laws governing the Universe (monovacuism, if you wish). Schellekens also dedicates a few pages to this propaganda - and various funny and subtle kinds of criticism invented by the physicists in both groups.

The anthropic people including Schellekens and Susskind claim that the "landscape revolution" is analogous to the Copernican revolution and other revolutions in science: stupid people used to think that they were terribly important (they believed in anthropocentrism) but brave scientists have shown that the humans were not so special, after all. The Earth is not a center of the Universe, and neither is our Sun or the Milky Way. The human DNA is not qualitatively different from the DNA of other animals. And perhaps, our Universe is just one among zillions of universes in the multiverse. The properties of elementary particles can't possibly be unique, can they? The Universe is a mess and it has always been one. :-)

Well, that's one story. But I also see a completely different story involving more recent breakthroughs in theoretical physics that are arguably more relevant for the question of predictability of the particle masses than Copernicus' adventures. During the last century or so, we have seen an incredible unification of concepts and observations that eventually allowed us to describe all of chemistry, engineering, and biology (thousands of materials, objects, and their diverse interactions) in terms of a single theory (QED) with one dimensionless parameter, the fine structure constant (and perhaps the proton-electron mass ratio), and even if you're interested in the other physical effects that are pretty much irrelevant for life (such as nuclear physics), we can describe everything by a similar theory with 28 parameters (the Standard Model; plus add General Relativity in a sloppy way to separately describe the gravitational phenomena). It is natural to expect that the missing step to complete the picture is analogous e.g. to the electroweak unification and it will make the remaining parameters calculable, much like the spectral frequencies of all atoms became calculable 80 years ago, and we seem to be damn close to completing this step. The Universe is elegant and it has been elegant even before the first moment when people noticed. ;-)

These are stories about two scientific "trends". These trends seem to have the opposite "signs". They are "derived" from our experience at different time scales. They are "derived" by selectively focusing on some stories while neglecting and humiliating others. I think that every rational person realizes that the answer to the question whether the anthropic explanation of the Standard Model or its unique derivation from a fundamental theory is the right approach doesn't necessarily have to mimic the answers to "similar" questions answered by Copernicus. It doesn't have to "reproduce" the uniqueness of QED, either. We are simply asking different questions than the previous generations and different questions sometimes have the same answers but they often have different answers. For example, the world has been increasing in size in Copernicus' and Hubble's time but so far it has never increased behind the boundaries where we can actually see anything. Many quantities - such as temperature - were shown to depend on the environment (distance from the Sun etc.) but it still seems that the particle masses and couplings we want to calculate are universal across those 14 billion light years of the visible Cosmos.

And the uniqueness has worked in fundamental physics but there are many stories close to fundamental physics where it didn't work and where we believe that historical coincidences played a critical role in determining some parameters.

I say that all sane people must be aware of the fact that we can't "derive" the answer to this completely new question by extrapolating the previous experience. But at the same moment, it seems that many people try to pretend that they believe that such an extrapolation is possible. Sorry but as long as you focus on rational arguments, such an extrapolation is impossible. There's no way to be sure. The "uniqueness" answer hasn't been proven; it is probably necessary to actually find the correct unique answer before we will know that the answer is unique. ;-) And the "anthropic principle" hasn't been proven, either. Whoever thinks that he has a simple philosophical proof of his attitude is sloppy. And whoever thinks that his answer must be correct because all other answers can be defined "not to be science" is an imbecile. And Nature doesn't give a damn how imbeciles define science: Not Even Woit.

When we discuss these anthropic questions, there exist various technical differences between field theory and string theory: string theory actually allows us to define the measure on moduli spaces, count the discrete vacua, and connect them to a unified cosmology via the eternal inflation and tunneling. Because the stringy realistic vacua are discrete, they are more specific and, in principle, completely localizable (even though one of the points of the anthropic approach is that you shouldn't even try to do it). Nevertheless, the deep essence of the anthropic argument seems to be identical in field theory and string theory. So we can ask:

Can the Standard Model parameters be derived from a fundamental theory?

We don't know the answer. Once people actually derive them, the answer will clearly be "Yes". The anthropic people say that the answer is almost certainly "No" and the rest of us says that their conclusion is premature.

Schellekens describes the reactions of the anthropic infidels as disgust (or even religion!) :-), denial, and derision but he also mentions that Burton Richter considers the anthropic people to be creationists. By the way, it is actually very subtle which group is closer to creationism: it depends on your optics.

Schellekens recalls some of the anthropic coincidences that seem to be necessary for life and offers us an anthropic checklist - four steps that help a careless reader to wash his brain and become an anthropic person, too. ;-) The checklist is rather clever, so let us look at it:

1. The Standard Model may not be the unique mathematical solution of any fundamental theory.
2. Not all alternative solutions allow observers.
3. The total number of solutions should be sufficiently large to make the existence of a solution with observers plausible.
4. We live in the most probable Universe which allows observers.

Why is it clever? Because he is "gradually" making the propositions "more anthropic" and the last one is nothing else than the hardcore anthropic assumption that people like myself clearly want to reject. However, I kind of accept the first statement. So where should I say "No" for the first time? It is actually hard to find the place. But I will find it in the middle of the point (3), anyway. ;-)

First, I tend to agree with (1). I find it unlikely that a fundamental theory - or even string theory with a selection mechanism - would make the rather messy Standard Model (with its parameters) a completely unique solution. After all, we know many other solutions to string theory and I am convinced that many (or most) of them will survive the test of time.

The statement (2) is almost clearly correct, too. For example, some stringy vacua with unbroken supersymmetry can be almost proven not to have any observers or intelligent observers. We don't have a full proof of it - because we can't really define observers and classify all conceivable "types of life" - but it is plausible that we could construct such an argument. One of Schellekens' powerful tools is to emphasize that we don't have to prove that "our island" in the parameter space is the only place that admits life (which seems extremely hard to argue because there can be discretely many "types of life"). It is enough to show that there are many generic places outside that almost certainly don't admit life.

Now, because I have accepted the points (1) and (2), Schellekens says that I have already adopted "some kind of anthropic reasoning" because there are places (different universes) where we don't live. Well, fair enough. It is "some kind" but I still haven't accepted (4), have I? :-) Just the fact that I don't live in the middle of ocean doesn't mean that I can't exactly calculate the the number of protons in the atoms dominating our atmosphere (nitrogen).

I kind of agree with the binary content of the point (3), too, but the precise explanation why I agree could be highly disappointing for Schellekens. If we make an estimate of the probability (or plausibility) that life is born somewhere in the multiverse allowed by the fundamental theory, the probability shouldn't be much smaller than one. The life shouldn't be a completely unexpected accident according to science.

However, one must be very careful how this probability of having life somewhere is calculated. Schellekens is now slowly trying to convert the readers to the irrational anthropic reasoning, in order for them to accept (4), too. Why? Because he wants you to believe that the probability that the life exists somewhere - among N universes - is essentially equal to N times P where P is the probability that the life is created in one "typical" universe (the formula gets corrected if N times P would be close to one or greater than one).

This could be a good order-of-magnitude estimate in an "egalitarian" multiverse where all universes have the same chance to host observers. But I think that this "egalitarianism" is simply incorrect and it is very important for this whole anthropic debate that this principle is incorrect. In fact, I can make the accurate calculation of the probability that a correct fundamental theory allows for observers somewhere on its landscape: the probability is not N times P but rather 100%. It's that simple.

We know that life exists, so if the theory is correct, it must predict life inside one of its solutions. The only problem could occur if no fundamental theory existed at all, but I choose to discard this possibility. If we only want to know whether it predicts life or not, it doesn't matter how many classical solutions it has and what is the distribution of the probabilities that each of them allows intelligent observers. What matters is that it contains at least one universe - ours - that admits life.

This "N times P" calculation is sloppy, ideological, and this ideology - the egalitarianism between vacua that are clearly different, non-equal, and hierarchical in many respects - is the essence of the anthropic fallacy. In my calculation, I didn't even have to multiply two numbers: you might think that it makes my calculation less mathematical. However, my result is actually exact, unlike the results of Schellekens' implicit formula.

It is interesting to look at Schellekens' calculation of the probability in (3) from one more viewpoint. He seems to require that the density of the stringy vacua in the vicinity of our region of the Standard Model parameter space should be huge, otherwise it is awkward to believe that any vacuum of string theory matches reality. I fundamentally disagree with this proposition. Here is my checklist to see why this proposition is irrational:

• The density of the stringy vacua near our locus in the SM parameter space is not infinite because the number of semirealistic stringy vacua is finite: so Schellekens can never be "completely satisfied".
• When you try to find out a "natural lower bound" for the density, you won't find an acceptable answer. For example, you might require that the small region that describes our Standard Model with the error margins of parameters as extracted from the 2008 measurements should contain at least one stringy vacuum, if calculated by the densities. But this "falsification" would clearly be irrational because such major decisions about the validity of a theory cannot depend on the number "2008" or some random coincidences about our present world.
• Moreover (and the following argument is related to the previous one), sometimes in the future, the measurements of the SM parameters will be more accurate, the error margins (and therefore the relevant region) will be smaller, and the number of vacua calculated in the "ball" around our point through the densities could drop well below one. In the future, the "test of sufficient density" is likely to fail even if it passes today. Sometimes in the future, this "density" test will fail. If you know so, shouldn't you agree that the test is failing already today?
  
• Once you agree that there exists no "sensible" lower bound on the density of stringy vacua near our locus, you will realize that it should have been completely expected that this criterion was nonsensical from the very beginning. When the density of stringy vacua near our point is (much) lower, it simply means that string theory will be (much) more predictive when it comes to the Standard Model parameters. There is nothing wrong with a theory that is more predictive. We have always believed that we were looking for predictive theories and if the supposed "paradigm shift" is that we must require the theories to be unpredictive, I simply disagree. Schellekens seems to believe otherwise: he thinks that every theory that is predictive is excluded and only theories that can be adjusted in any way to match the observations by chance are allowed. I beg to differ.
• To summarize, the only sensible "phenomenological" way to falsify string theory (or another hypothetical theory with many vacua) is to show that the number of vacua in the vicinity of our locus in the SM parameter space, plus minus the known error margins, is strictly equal zero. Any other "falsification" claiming that the density seems "too low" is a fallacy based on the (ludicrous) assumption that theories are never allowed to predict anything.
  

While in (3) this fallacy was incorporated "silently" - the point (3) was written so that you make the "N times P" error yourself - it is written explicitly in point (4) which is nothing else than a logically and scientifically unjustifiable left-wing propaganda.

Let me say one more comment. The anthropic selection could be "partially correct" etc. but even if it is so, the interesting observations are the aspects in which the anthropic reasoning is incorrect. This is where the new patterns and new scientific insights are located. So it would be highly counterproductive to assume that the anthropic assumptions of genericity are "nearly universal".

And one more observation about the point (3). I calculated the probability that a viable universe is somewhere in the landscape of the fundamental theory. That was equal to 100%. But if I give you a Hartle-Hawking-like cosmological selection criterion, it secretly assumes that only one universe gets materialized, not all of them simultaneously, and the formula can produce a different probability for the realization of a (any) universe - and a different formula for the probability that life emerges. The result could be much smaller than 100%. That's true. But what is not true is the implicit assumption of the anthropic people that if I require the probability to be calculated in this way and if I want the result to be close to 100%, I must allow (almost) all vacua on the landscape to contribute. The final section of this essay describes a very dramatic scenario how the probability could be high even if the vast majority of the landscape had a highly suppressed weight in the probabilistic measure. But even if you find the scenario unlikely, there exist less dramatic possibilities where only a tiny fraction of the landscape contributes.

So the answers are

1. Yes.
2. Yes.
3. Yes, but the answer is trivial and the very question tries to make you accept a wrong formula.
4. No.

The proponents of the anthropic fallacy, including Schellekens, are just not ready or not willing to admit that various calculations they make are just order-of-magnitude estimates that incorrectly assume that certain functions are constants in vast sets of vacua (or in cubed or hypercubed miles of the multiverse). But these quantities and densities of life etc. are not constant. The more we know about the theory, the more we know about the non-constancy and the more accurate calculations we can make. The more we know, the further we are from the fuzzy anthropic ideas about the location of our vacuum in the landscape. It is the very goal of scientific progress to get as far from these fuzzy pictures as we can.

In order to show how political, vague, and socially dependent the anthropic methods are, let me consider the following gedanken experiment. Imagine that you establish a new country and you invite 100 million settlers. Now, the question is: What is the expected number of Fields medal winners? The anthropic people would divide the population by the world population, multiply it by the total number of the Fields medal winners who are alive, and they would get something like 1 Fields medal winner.

But what if I tell you that 99 million settlers are female? Now, it will be an inconvenient question for the left-wing anthropic people. Some of them will say that the probability hasn't changed at all because the sex doesn't matter. The more reasonable ones will make a new calculation and their estimate will decrease by a factor of 100 because there are no female Fields medal winners which is why only the male ones contribute to the expectation value: their total expected number of Fields medal winners will be smaller than one, essentially zero.

Eventually, someone manages to look at the people and among the 1 million of the male settlers, they find Witten, Tao, and Connes. So the correct answer is 3, after all. But the previous estimates turn out to be useless.

The procedures to quantify the phenomenological viability of the multiverse and its subsets are completely analogous. The more we know, the more irrelevant the initial estimates become. And they often turn out to be completely wrong. The anthropic people usually assume that certain quantities, densities, and probabilities are constant for all members of vast sets. But it matters how finely you divide the set into subsets: will you allow your grad students to count the F-theoretical flux vacua and heterotic vacua (or males and females) separately? If you want to get the accurate result, you should divide it to the individual members and do the exact calculation.

Let me mention another, more physical example explaining why we often need to know the exact (or almost exact) answers. The fusion in the Sun is important for our lives but it can only work well if the mass of the helium nucleus is slightly lower than the mass of two protons and two neutrons in the two deuterium nuclei (apologies for oversimplifications, this example is easy to talk about). But you might think that these nuclei are generic states of QCD and by dimensional analysis, the difference of their masses is comparable to the QCD scale. That would generate too high temperatures and maybe other problems. However, the argument is wrong. The energy generated by fusion is comparable to 1% of E=mc^2 only.

And I don't need to assume life to find the 1% figure: a better calculation rooted in QCD or nuclear physics is enough. Some "deeper" patterns that go beyond order-of-magnitude estimates are often damn important for figuring out whether a physical system allows life, among other things. Assuming that all vacua in the landscape have the same probability to host life is analogous to the assumption above that all energy differences in nuclear physics are comparable to the QCD scale. They're not and in many cases, there is a very good scientific reason (not just chance or the requirement of life) why some of them are much smaller.

The very program of the anthropic approach is to forget and deny all deeper patterns and all more accurate and more detailed calculations, to replace our sharp picture of the world by a permanent colorless uniform fog of ignorance. The very goal of this ideology is to convince physicists not to improve their understanding of Nature and to replace exact calculations by low-brow order-of-magnitude estimates. The anthropic reasoning hasn't worked in previous scientific revolutions because more specific explanations were always found and the idea that it is exactly around 2008 when the sharp answers disappear and the anthropic fog becomes relevant for all open questions is a form of fine-tuning. There is no reason for the number 2008 to play such a special role in the scheme of the Universe. ;-)

The assumption that all vacua in the landscape have the same probabilities etc. and we must live in a vacuum in the class that dominates the "total number", whatever the artificial boundaries of the class should be, seems obviously false to me. There exist all kinds of hierarchies, including hierarchies that have neither an anthropic explanation nor a universally acceptable scientific explanation (such as the QCD theta-angle), that show that our vacuum is not completely generic. We kind of know that we have three generations (or the Euler character of a Calabi-Yau) and with further high-energy experiments, it is plausible that we will be able to "measure" other invariants describing the correct compactification, its topology, the numerical values of fluxes, the number of branes, and the shape of the throats. The idea that there can't ever be progress in science is also ludicrous and it's been falsified zillions of times. The only question is how fast the progress will be. We're not guaranteed anything.

The idea that we must live in the "gray" zone of the "most generic" and "uninteresting" vacua could be a great theory for insect in China because it may be the most numerous group of living objects, classified by their country and their class in the Linnaean taxonomy. But this theory simply doesn't look good enough for certain mammals in the Czech Republic.

Schellekens and other anthropic people say that they would be worried if some feature of our world were not "generic" in the stringy vacua - a point analogous to their requirement of a "high density" near our locus. I would not be worried because there exists no law that we would have to be generic. After all, the exact properties of our life and our nationality require the exact vacuum we live in, despite the low density of vacua around (or despite the low population of the nation). But even if someone convinced me that our vacuum should be generic (in "most aspects"), I don't think that anyone knows what the right measure to determine the genericity should be: the "each vacuum has the same vote" measure is surely not good enough because of many reasons, for example because the total number of all vacua (including the AdS5 x S5 vacua) is infinite and the uniform probability measure can't be normalized. It is even wrong to use the counting based on volumes of the Standard Model parameter space because the Standard Model is clearly neither the first nor the last effective field theory that can be written down: it only corresponds to the state of our experimental knowledge of particle physics as of 1973-2008. The QED used to have a smaller parameter space and the MSSM or other future effective theories will require different, possibly larger parameter spaces.

Because the anthropic people rely on so many concepts that are only relevant in 2008, what they're doing is a statistical interpretation of the history of physics, with a focus on the present era, not physics itself. Note that I am in no way saying the "same thing" as Peter Woit. I am actually finding particular material flaws in various arguments while the obnoxious repetitive crackpot only says (731 times) that none of these things is science and he doesn't even have to think about any of the arguments - which is just an arrogant propagandistic nonsense and surely not a contribution to the scientific debate.

We may not be the most special creatures (and universe) in the multiverse (even though Leibniz used to say that our world/life is the best possible world/life) but we are not the most generic (or messy) ones, either. Both of these assumptions are irrational philosophical prejudices and unjustified extrapolations from cases where they happened to work. Now, we can pretty much sit at a reasonably generic point of a statistical distribution but you can't ever be sure how close to the central or most likely values you are. For different quantities, the distance from the "genericity" may be very different. There is clearly no universal answer.

Sometimes you are very generic, and then the insight about your genericity is not too interesting because it carries low information. Sometimes you are special. The information clarifying why you are so special is higher (if a theory predicts a very special feature, it is very predictive) but such cases are less likely. There is a trade-off going on here and whoever thinks that the very anthropic assumptions can lead to a high-information conclusion that is nevertheless very likely to be true, without finding non-anthropic arguments and mechanisms, is clearly making a logical error.

There is no rational reason to think that individual vacua should carry the same "weight" in the anthropic distribution. And if you use the very existence of life to deduce something about the low-energy parameters, you won't get too much interesting information because we know much more than the fact that life exists in our Universe. We also know the values of all low-energy parameters that make this life (and many other things) possible. Anything that can be derived about our compactification from the existence of life can clearly be derived from the known values of the parameters, too (because the life itself can be derived from them). Physicists should finally appreciate that it is legal for them to use all the known experimental data (including those found in the near future) in their search for the correct theory (and its vacuum). It used to be legal in the past, too. ;-)

Why would you ever use the incomplete information about the existence of life only rather than the full information you can have? It looks like a children's game where a kid has to determine something without looking somewhere. But scientists are allowed to look, aren't they? Note that it is still the same complaint against the "selection fallacy" that I have already raised many times. When the anthropic people calculated a probability as "N times P" (Schellekens in his point (3)), they were also using an incomplete information, representing every vacuum by a "generic representative" for some class even though more accurate calculations are clearly possible as long as people keep on improving and sharpening their knowledge about particular vacua and abilities to deal with them.

Laws that maximize life naturally

Finally, I want to say that the ultimate laws governing the vacuum selection can be "naturally" compatible with the existence of life in the preferred Universes.

A universe that admits life has to satisfy all kinds of features and many of them have a quantitative character: various parameters and ratios have to be small. You have to have a lot of hierarchies of scales (a small cosmological constant, an electroweak-Planck gap, fermionic mass hierarchies), a lot of different long-lived states (nuclei, molecules) in the spectrum that have sufficiently different geometries, and so on. Imagine that you create a similar "index of life magic" I_{LM} as a function of various "healthy gaps" in such a way that the vacua with a higher value of the index can reasonably be expected to admit life "more easily" than the vacua with a low value of the index.

This index is an artificial human invention but it is completely plausible that there exists a natural formula - e.g. one derivable from a generalization of a Hartle-Hawking wave function - that has similar consequences and that naturally makes it more likely for life to appear in the universe that is also predicted to be more likely by a cosmological HH-like selection formula.

Do you think that such a hypothesis is a form of a conspiracy theory? Feel free to believe it is. But the objects that make life extremely unlikely in certain environments are just continuous numbers: discrete conditions only reduce the number of viable vacua by a factor comparable to one (such as two). And continuous numbers often like to enter formulae. When you have a Hartle-Hawking formula dictating the probability of different vacua (or low-energy parameters) after an early era of cosmology, it usually depends on these numbers: recall the dependence on the cosmological constant (with the problematic sign). The dependence can be strong, it is almost guaranteed that there is a bias, and the probability that the bias is in the direction that favors the "viable" vacua is significant, maybe even higher than 50% (a priori). When you actually fill in the details of this theory, you will be able to say that the probability is 100%. ;-)

If this picture is correct, there can exist an old-fashioned scientific, non-anthropic explanation why we live in a universe where life looks a priori easy. I find this picture speculative but from the viewpoint of eternity, it is very plausible. Viability can be imprinted to our world through the basic laws of early cosmology. Every "theorem" that tried to prove that similar calculations must be impossible has been circular so far: all of them had to assume that our Universe belongs to the gray zone and it has no theoretical or phenomenological "fingerprints" or special features that could identify it - and they proudly proved that one can't ever identify such a vacuum by its fingerprints in a polynomial time (sorry, Frederik and Michael, but that's what you're doing).

I wouldn't make a bet that someone will actually find such a non-anthropic explanation of the viability of our Universe in a few years but many key events in the history of science have been unexpected. Moreover, the belief that the anthropic fog won't be falsified in a near future (a belief I share) is something different than a belief that it is the correct answer (which I don't share). People naturally focus on research directions where they can make progress, so I am certainly not afraid that every talented physicist is going to work on a hopeless project. But even if some project loses man-hours, it doesn't mean that there can't ever be a new breakthrough in this project. But even if you don't believe that such new insights about the vacuum selection problem will be found in the future, it is probably more fruitful for the physicists to focus on attempts to find new patterns and laws rather than self-fulfilling attempts to prove that science is over. ;-)

Because the arguments that our Universe must be generic (and there is no extra information we can ever learn about it) seem to be circular and seem to contradict the whole history of science which has always seen some additional progress, I think it is reasonable for a physicist to expect that every "generic" description of a system we don't understand is a temporary state of affairs. The more we will know, the more the fuzzy anthropic fog is going to be replaced by a sharper picture full of fascinating insights, important patterns, illuminating relationships, exact numbers, and specific links to previous theories as well as observations, insights that are similar to hundreds of those that have already been found.

And that's the memo.

Monckton, APS, and Medusa

The Register published an entertaining article about the funny story involving Christopher Monckton and the American Physical Society.

Recall that Jeff Marque, an APS editor, wrote in their recent newsletter addressed to a small subgroup of the APS called "Forum on Physics & Society" an obvious truism, namely that a considerable fraction of the scientific community are climate skeptics. They opened a rare arena for scientific arguments about this issue.

Needless to say, that was already way too much for the true believers. In an article proudly called Physicists forced to reaffirm that human-caused global warming is “incontrovertible”, Joe Romm of Climate Progress initiated an e-mail campaign and encouraged hundreds of readers of his website to do the following:

So this editor who single-handedly smeared the good name of the American Physical Society and the 50,000 physicists it represents is one “Jeff Marque, Senior Staff Physicist at Beckman Coulter Corporation, 1050 Page Mill Rd., MSY-14, Palo Alto, CA 94304, jjmarque@sbcglobal.net.” Please do email him and his bosses (whose names and e-mails I will provide below) to let them know your thoughts.

What Marque has does [sic] is so beyond the realm of real scientific debate that he should be fired from his editorial position.

So you should imagine those hundreds of incoherent yet angry e-mails that the AGW zealots sent to Marque and his bosses (including Lawrence Krauss, the former FPS chair). Because of his blasphemy, they try to "fire" Jeff Marque - who is not even paid for this minor "job" of an editor. ;-) That's an example how the activist foam of the society starts to influence what's going on in the world. They can even fire people from jobs that don't exist! ;-)

(Recall how easy it was for Jo Abbess, an activist chick, to completely change an article written by the BBC.)

Nevertheless, the APS has published an article by Lord Monckton, Climate Sensitivity Reconsidered, which not only summarizes some of the well-known inconsistencies (such as the wrong fingerprint) in the greenhouse model of the climate but also offers the readers an insightful review of the IPCC methodology.

Among many other things, Monckton explains that the key (and high) IPCC's figure for the climate sensitivity is based on one (1) scientific paper that uses another number "kappa" from two other papers - one of which was written by a person who has promoted his or her own paper through the IPCC. It doesn't exactly look like 2,500 people calculating the sensitivity.



The AGW mujahideens have eventually convinced the APS to add the following disclaimer above Monckton's invited contribution. The health warning (don't look at Medusa!) was written in red ink:

The following article has not undergone any scientific peer review. Its conclusions are in disagreement with the overwhelming opinion of the world scientific community. The Council of the American Physical Society disagrees with this article's conclusions.

Some secret sources of mine indicate that this disclaimer was added by Lawrence Krauss, a well-known far-left critic of physics, who also recently claimed that the cosmologists are destroying the Universe by making observations.

Of course, Lord Monckton and many members of the scientific community have complained because his contribution was an invited one and the insulting fundamentalist disclaimer above was not a part of their agreement.

Moreover, the disclaimer is completely illogical, at least from a scientist's viewpoint. If the paper were not scientifically peer-reviewed in any way, how could they know whether its conclusions agree with the opinion of the "scientific community" or not? ;-) Only the people who don't read the bulk of any scientific papers could know whether they agree with a paper or not without reading it. They're supporting the AGW God regardless of the bulk of all papers and they seem to be particularly proud about their pure belief uncontaminatable by any arguments!

After some additional battles, the red ink comment was replaced by the following remark written in ordinary black ink (the same paragraph was also added above the consensus scientists' contribution):

The following article has not undergone any scientific peer review, since that is not normal procedure for American Physical Society newsletters. The American Physical Society reaffirms the following position on climate change, adopted by its governing body, the APS Council, on November 18, 2007: "Emissions of greenhouse gases from human activities are changing the atmosphere in ways that affect the Earth's climate."

You have heard the holy word again and you will hear it infinitely many times in the future. Amen. That's all very funny. Imagine that a similar comment would be written about an issue that is so far remaining a subject to the scientific method. For example: "The APS reaffirms its official collective position that the cosmological evolution follows the Big Bang theory with dark energy and cold dark matter and particle physics beyond the Standard Model obeys the laws of string theory." ;-) That would be funny, right?

And I am probably being too optimistic here. The APS could also adopt the official position of the PI and announce that "the members of our society are certain the world follows the laws of ekpyrotic loop quantum cosmology with a variable speed of light, two metric tensors, and 30+ braided octopi swimming in the spin foam." :-)

At any rate, the American physicists are no longer treated as sui iuris. They must be protected from Lord Monckton's blasphemy much like little kids must be protected from beer. And frankly speaking, many of them fail to be sui iuris, indeed. There are just so many of them who have been so easily manipulated by the activist foam that I can no longer respect them as honest scientists even though many of them have contributed to high-energy physics and other disciplines.

And that's the memo.

Bonus

A TV regulating institution (Ofcom) in the U.K. decided that The Great Global Warming Swindle didn't materially mislead the viewers to cause harm or offense (i.e. Ofcom agreed that every single complaint by Myles Allen, Phil Jones, and "37 professors" was unjustifiable) but it did misinterpret some climate alarmists' words: see the full verdict and Steve McIntyre's comments. It could be the case but most of the specific accusations by the censor seem manifestly untrue to me.

For example, Fred Singer said in the program that David King argued that Antarctica would become the only habitable place on Earth by the end of the century. The censor argued that it was not true. I can tell you Fred's comment was true and we even know where King said exactly this thing. It was in the Independent on Sunday, May 2, 2004. See this Spiked article or make a Google search. The exact quote was:

Antarctica is likely to be the world's only habitable continent by the end of this century if global warming remains unchecked.

King was said to announce this far-reaching conclusion in a talk to a climate group. Now, the Independent on Sunday could have been inaccurate (although the quotation has never been challenged!). But if it is the case, it is the Independent on Sunday, and not Channel 4 or Fred Singer, who should be chastised! The alarmists are saying tons of similar mad things every day, so even if this particular quote were inaccurate, the big message, namely that the alarmists are lunatics, is accurate.

Oceans, not CO2, drove continental warming

Roger Pielke Sr discusses a new peer-reviewed skeptical climatological paper by G.P. Compo and P.D. Sardeshmukh,

Oceanic influences on recent continental warming (full text; abstract is here)

in Climate Dynamics (2008). They treat the known profiles of the ocean temperature as a possible driver and argue that this function of time is enough to reproduce the observed continental temperatures almost accurately.



This remark means that the greenhouse effect above the land is not among the most important effects while the temperature change of the oceans is primary. However, they can't say why the temperature of the oceans was changing. And of course, the greenhouse effect (mostly above the oceans) can still play a significant role for this question. But it doesn't have to.

The very statement that the ocean temperature is sufficient as a "driver" to explain the continental temperature sounds good and plausible (because of the high heat capacity of the oceans) but I am afraid that it is another example of the logical fallacy emphasized by Roy Spencer. They haven't really proven it. Correlation is not causation and even in the cases where it is, you can't quite know the direction of the causal relationship...

One of the messages of the paper is that the ocean temperature should be studied more carefully and the climate should be investigated in the regional context, not just through the global averages that completely overlook many of the essential phenomena: the paper actually shows that the regional patterns were predicted completely incorrectly by two popular classes of climate models.

Carl Icahn, now on Yahoo's board, will help Microsoft

Carl Icahn, the 46th richest person in the world, won his proxy contest and was named a member of Yahoo's board. He considers Yahoo's refusal to be bought by Microsoft irrational, and so does your humble correspondent. We will see whether his new chair will be enough for the deal.

Bimetric pseudoscience and ghosts

This month, at least two preprints about "bimetric" theories of gravity have been submitted to the arXiv: one of them came from the Imperial College (IC) and the other one was written at the Perimeter Institute (PI).

Here, I want to explain why this kind of writing is ridiculously bad and lethally flawed if understood as science. I claim that the authors of these papers - and dozens of previous papers about the same subject - must be unaware of virtually all elementary facts about physics to be explained below and they should have been failed in their field theory courses.



Two geometries, two gravities, two Newtons? It may sound attractive :-) but it is physically unacceptable.

The IC paper talks about "two metric tensors" - as an example of the Variable Speed of Light misapproach - but there is really one metric tensor only (supplemented by a scalar with unusual interactions): the only thing that is "doubled" are the frames. You can define different frames - different conventions what you mean by a metric tensor and by distances.

Normally, frames (e.g. Einstein frame and string frame in string theory) are related to each other by scaling. In the IC case, they differ by additive terms - such as "∂_μ φ ∂_ν φ" - which means that they generally induce different causal structures but there is still one independent light spin-2 field so the adjective "bimetric" is a misnomer.

It is also wrong to call it a "Variable Speed of Light" theory because the unique metric tensor still defines a unique and fixed value of "c". Whether the IC paper defines a consistent theory depends on details but it is surely not an attractive or a well-motivated theory.

The IP paper is even more seriously flawed because it literally wants to have two metric tensors, "g" and "h", that can be used to measure distances on a manifold. We will explain that it is a physically inconsistent setup because

1. there can only be one general covariance to remove ghosts
2. if one introduces new non-local symmetries to get rid of the remaining ghosts, the second metric tensor becomes massive and disappears from long-distance physics
3. consistent theories of quantum gravity automatically imply that there can only be one independent metric tensor

Ghosts in theories including fields with spin

So let me begin with an explanation what ghosts are. In physics, this concept has a somewhat more specific and abstract meaning than e.g. ghosts from the Ghostbusters movie. ;-) Physicists use the term for two related but different objects:

1. bad ghosts: states in the Hilbert space whose (squared) norm is negative i.e. that have a negative probability to exist
2. good ghosts: Faddeev-Popov ghost fields that are very convenient to deal with local (gauge) symmetries
   

The relationship between bad ghosts and good ghosts is that the refinement of a theory that employs good ghosts replaces the original Hilbert space with the physical Hilbert space of cohomologies of the BRST operator, Q, and if the theory is consistent, this (reduced) physical Hilbert space is free of bad ghosts. That's necessary for a theory to have a physical meaning because negative probabilities can't occur in reality. For example, no one has ever won -30% of elections, as long as he participated at least in one. :-)



Below, I will talk about bad ghosts only. In the first place, we should ask:

Why there should be any bad ghosts?

Well, the reason is simple. Consider a (non-gravitational) theory with a field whose spin is one or higher (spin-0 and spin-1/2 fields won't generate any ghosts: recall that the psi-dagger-psi Dirac inner product, measuring the probability density, is positively definite), for example QCD with spin-one Yang-Mills fields. When you draw the "t=0" slice and try to quantize it - which you eventually have to do because our world is a quantum world - you will have operators A_μ whose Fourier modes give you creation and annihilation operators for particles with certain momenta.

What is the norm of the one-particle states created by these operators? You may see that the inner product of the state created by A_μ with the state created by A_ν is actually proportional to g_μν, the metric tensor. This fact is pretty much required by the Lorentz invariance - the metric tensor is the only "universal" tensor with these indices - but you can derive it explicitly from the action, too. (A priori, you might think that the inner product can also depend on the timelike vector associated with the t=0 slice, but the set of 1-particle states is actually Lorentz-covariant and the inner product doesn't depend on the slicing, after all.)

Now, the metric tensor g_μν is indefinite: when you write it in a diagonal basis, some of its entries must be negative (because the space and time have opposite signature). Most of the entries of vectors and tensors are the purely spatial ones, and these have to generate the positively definite one-particle states in the Hilbert space leading to positive probabilities (regardless of your sign convention for the metric).

The negative-normed entries correspond to quanta - particles - that would lead to negative probabilities. Whenever you would create a final state with such a particle, its probability would be negative (a negative multiple of the squared complex |amplitude|), leading to logically unacceptable predictions - an inconsistent theory. The only way how such a theory could possibly survive is that such ghosts are never produced if you don't have them in the initial state.

Decoupling the ghosts

So if you want to save your theory, you must assume that there are no ghosts to start with. More importantly, the theory must also imply that if there are no ghosts to start with, they are never produced by the evolution. The probability amplitude (for a scattering etc.) including one bad ghost or more ghosts (in the final state) and many ordinary particles (in the final and initial state) must be zero. We say that the ghosts must be decoupled.

(In a theory treated with good, Faddeev-Popov ghosts, it is no longer true that the probability with all kinds of ghosts in the final state must vanish. Instead, the amplitudes with BRST-exact states must vanish, and they automatically do if the BRST axioms such as Q^2=0 are satisfied. Let us follow the old treatment without the good ghosts below.)

Now, it is a very nontrivial requirement that the ghosts must be decoupled from an arbitrary combination of ordinary particles. When you have a "generic" theory where ghosts (which are just "some" parts of your tensorial fields, after all) interact with the normal matter, you may be sure that most of the probability amplitudes will be nonzero. How can you possibly make all of them zero?

The answer is a "gauge invariance". You must "pay" gauge invariance for each potential ghost, and because it is so hard to find a lot of gauge invariance in your theory, you normally have enough gauge invariance to kill the timelike components only. That's why the timelike components must be those associated with the negative-normed one-particle states (regardless of your metric sign conventions).

At every point of spacetime, there must exist a parameter of gauge invariance for each component of bad ghost fields. This is enough. Why? Because the scattering amplitudes are encoded in the correlators of various operators - i.e. in Green's functions - and the operator corresponding to a bad ghost may be expressed, up to a momentum-dependent rescaling, as "∂_μ j^μ" which vanishes because the corresponding current "j" is conserved. It is conserved because of Noether's theorem applied to the global part of the corresponding gauge symmetry.

You can see that the very condition that a quantum version of your theory exists severely constrains how the theory can look like. In classical physics, you might think that any kind of field theory is just fine. You might write any field equations controlling any fields you like. However, most of them would lead to quantum theories that predict negative probabilities and they're not allowed. It follows that fields with spin can't be added arbitrarily: you need a gauge symmetry for each time-like (negative-normed) component of such fields!

That's great. So let us look whether we have enough gauge symmetry to kill the ghosts. Yes, we do. For example, in QCD whose gauge group is SU(3), there are eight Lorentz vectors "A_μ": the 1...8 index is the adjoint index of the 8-dimensional SU(3) Lie algebra. But we also have 8 currents "j_μ" and 8 corresponding parameters of SU(3) transformations at every point. If you think about it, this counting obviously works for every gauge group in every Yang-Mills theory.

Modification for spin-3/2 and spin-2

We will begin with the most difficult case, the spin-3/2 fields.

If the spin is 3/2 (i.e. 1.5), you deal with Rarita-Schwinger fields that effectively carry one spinor index and one vector index. The spinor index would generate a positively definite (=ghost-free) Hilbert space, like the Weyl or Dirac field, but the vector index can go timelike again. Once again, you are threatened by ghosts and negative probabilities. And once again, you need a local symmetry - and the corresponding current - that saves your theory.

How many parameters such a local symmetry should have? Well, if the vector index is "0" (time), you obtain ghosts. But the spinor index can still be anything: the ghosts have many components. There is a whole spinor of ghosts and the corresponding gauge symmetry to kill these ghosts must therefore be a spinor, too. Now, gauge symmetries (and conservation laws) whose parameters carry a spin are heavily constrained by the Coleman-Mandula theorem and its modern refinements. If you wanted a conservation law for too difficult an object (with a high spin), pretty much every momentum of every particle would have to be conserved and the interactions would vanish: too bad even for a remotely realistic theory.

For spin 1/2 conserved quantities, there exists one possibility, and it is called supersymmetry: the conserved charges are called supercharges and they transform as a spinor or spinors. If you want a consistent, ghost-free quantum theory with spin-3/2 fields, it must respect (local) supersymmetry! By pure algebra, you can argue that the anticommutator of two supersymmetries includes a (local) spacetime translation, so the coordinate reparametrizations must automatically be a part of the story. With spin-3/2 fields and nonzero interactions, you must inevitably deal with supergravity, a theory that includes both gravitinos and gravitons.

The spin 1/2 of the supercharge is already pretty high and the conservation law for the supercharges - which is equivalent to the symmetry called supersymmetry - is very constraining. The maximum number of supercharges that a physical theory can possibly have is 32 real components which is equivalent to one real chiral spinor in 11 dimensions or N=8 (complex chiral) Weyl spinors in four dimensions. This "N=8 supergravity" is extremely constrained: its low-energy interactions are fully determined by the required supersymmetry. The less supersymmetry you require, the more free and unconstrained your model building becomes. For N smaller or equal to 4, you can get non-gravitational yet supersymmetric theories but because they're non-gravitational, the supersymmetry must only be global, not local!

Now the main point: spin two

But spinors and supersymmetry might be too complex for some readers, so let's return to an integer spin, namely spin-2. Nevertheless, I will still have to assume that the reader knows why gravity must be carried by spin-2 particles i.e. that the arrogant and mostly anonymous imbeciles from Not Even Wrong and similar dumping grounds of the Internet no longer visit this blog. ;-)

Imagine that you deal with a spin-2 field h_μν - such as the metric tensor - that contains something like the normal kinetic term in the Lagrangian. Again, the Fourier modes of this quantum field will give you creation and annihilation operators. The inner product of the states created by h_μν and by h_μ'ν' will be proportional to something like g_μμ' g_νν'. Or another product of two metric tensors with these four indices or one of their linear combinations. If exactly two of these four indices are timelike (i.e. 0), you may obtain a negative result. For example, "g_00 g_33" is negative.

It follows that the h_01, h_02, h_03 components of the tensor field create ghosts. There are D-1=3 of them and you need roughly D-1 of the gauge parameters, too. Essentially a whole spacetime vector. If you carefully analyze the index structure, you will find out that the conserved currents must be components of a tensor that you may call the stress-energy tensor T_μν. This tensor must be conserved and because its divergence "∂^μ T_μν" must be related to the bad components of the tensor "h" you started with, you may see that the corresponding transformation of "h" must coincide with the standard transformation rule of the metric tensor under the coordinate transformations.

In fact, coordinate reparametrizations are the only local transformations of fields whose infinitesimal parameters naturally transform as vectors.

In other words, the only way how a spin-2 field can be nontrivially interacting with the world, while generating no bad ghosts, is to identify the field with the metric tensor in a generally covariant theory. Because gauge invariance may be viewed as a "fundamental concept", you may derive general relativity from this alternative starting point. See also Gravity from spin-2 gauge invariance.

Fine: so can you have two metric tensors?

You would need "two independent reparameterization invariances". That's not possible in a physically acceptable and interesting theory. When you consider one manifold, there only exists one set of coordinates, after all. So there are only D functions that determine the relationship between two choices of the coordinate system: D parameters of a local symmetry. (Let me not discuss the difference between D-1 and D, it's too subtle.)

In fact, there exists a loophole - a method to have two or more metric tensors; see Arkani-Hamed, Georgi, Schwartz (AGS) based on generalized deconstruction (a phenomenologist's toy model for extra dimensions). However, when you follow their analysis of the physics that follows from their approach, you will find out that only one metric tensor - the "real one" - remains massless. The other one acquires a mass and disappears from the long-distance physics. In fact, their approach is the most natural method to analyze massive spin-2 fields.

Morally speaking, the other spin-2 field in the AGS picture has a similar character as the massive Kaluza-Klein modes of the graviton (or even the massive spin-2 fields in string-theoretical tower of states): in all cases, there are very manifest reasons why the new spin-2 field cannot be massless. You shouldn't view the AGS theory as a very low-energy theory because the theory breaks down as an effective theory above the energy scale (cutoff) that goes to zero (=the theory breaks down everywhere) if the mass of the other graviton itself goes to zero, even though the cutoff goes to zero more slowly than the mass (it is a kind of weighted geometric average of the mass of the massive graviton and the Planck scale).

So if you want to consider theories similar to one envisioned by the IP paper and others - where you can literally measure distances on a large manifold by two independent metric tensors - you are inevitably led to an inconsistent theory with ghosts. A good student should be able to comprehend - and even re-discover - all these facts in a few hours as a part of one homework exercise. People like Magueijo and Hossenfelder couldn't get them at least since 2001 when the wrong bimetric theories first appeared in the literature.

One metric tensor in string theory

Every good field theorist knows why these bimetric papers, and many similar papers, are just wrong. You don't really need to know string theory to make such analyses. Nevertheless, string theory gives us a particularly clear picture why there can't be several massless spin-2 tensors.

You may often hear the crackpots saying that string theory makes no predictions about the reality. Well, it makes tons of predictions. For example, it implies that virtually every paper that the critics' friends have ever written must be completely wrong. It predicts that none of their predictions can ever materialize. Isn't this a powerful prediction, too?

In string theory, you don't have to work hard to derive similar qualitative facts - e.g. that the number of gravitons equals one and not two: they automatically follow from it, from its own technical tools that we're going to look at. I would be skeptical about any theory that doesn't naturally imply any of these general facts about quantum fields. Of course, no theory besides string theory does such things which is one of dozens of reasons why I am skeptical about any non-stringy way to go beyond quantum field theory, to say the very least.

Why is there one metric tensor in any background of string theory, including every single vacuum from the proverbial landscape of 10^{500} solutions? Well, it just seems to be true in every vacuum we have ever seen - perturbatively or nonperturbatively. However, perturbative string theory makes the answer exceptionally transparent and let's look at it.

We will begin with bosonic string theory. The ground state of one string is a tachyon. And you may add the alpha-oscillator excitations. Already the first excitation brings you to the massless level. Two excitations already create a massive particle. So if you're only interested in the massless spectrum, you can only add one excitation in the open string case - generating a spin-1 field - or two excitations (left-moving and right-moving) in the closed string case - generating a spin-2 field.

The open strings can carry additional labels - the Chan-Paton factors (colors associated with the endpoints) - so you can have many components of a spin-1 field. In fact, the Chan-Paton factors become two indices and that's how you generate the whole "square matrix" of the gauge fields, transforming in the adjoint representation.

However, the closed strings don't carry any additional labels similar to the Chan-Paton factors. For example, closed strings don't have any endpoints or other special places that could support additional degrees of freedom. Consequently, the spin-2 massless graviton is inevitably unique. Nothing changes about this conclusion even if you compactify some of the dimensions. Any excitation of the compactified degrees of freedom increases the squared mass. So if you don't want to surpass the massless level, you cannot combine the compactified excitations with the excitations of the noncompact dimensions (that define the "ordinary" spin).

An analogous counting applies to the NS-NS sector of the superstring. Its ground state is a tachyon, too. (This particular tachyon becomes unphysical due to the GSO projections.) The only difference is that the squared mass is 1/2 of the bosonic one and you can work with half-integer-moded fermionic oscillators, too.

The vertex operator - a conformal field theory operator whose correlators are used to calculate the scattering amplitudes for a particular particle in string theory - corresponding to the graviton is proportional to "∂ X_μ(z) ∂* X_ν(z*)". By looking at this object, you can also see that there is only "one type" of the graviton that you can construct. There is only one worldsheet, with one set of coordinates, z and z*, and its embedding into the conventional spacetime is only described by one set of the fields X_μ(z,z*).

There is just no way to ever get two gravitons (or two metric tensors) with indices along the large spacetime coordinates. The only, uninteresting exception is when you imagine that the two metric tensors belong to two "subtheories" that don't interact with one another at all. In this case, you can even have two independent coordinate reparametrizations. Operationally speaking, the other "segment" of the Universe besides your own doesn't really exist. Andrei Linde used this vision - that there can exist completely decoupled worlds on top of ours - to motivate some ideas about the multiverse. The IP paper cited Linde's paper but Linde has clearly nothing to do with the crackpot enterprise of writing theories with several interacting metric tensors!

By the way, string theory has its own, completely new technical way to prove that the ghosts decouple: you don't have to talk about the currents "j" in spacetime. In fact, you can prove that the decoupled unphysical components of fields - such as ghost gluons and ghost gravitons - have vertex operators that can be written as a total derivative of another operator with respect to one or two worldsheet coordinates. Consequently, the integrated vertex operator (over the effectively compact worldsheet) vanishes, and so does the scattering amplitude.

In the BRST treatment including the good ghosts, the arguments would be slightly more sophisticated but they would be equally powerful to derive the conclusions we need.

Related facts about the stringy spectrum

Similar arguments lead to many other, related general conclusions or general predictions of string theory, if you wish. There can't exist massless fields with spin higher than 2 - not even 5/2! ;-) The fields with spin-3/2 must be gravitinos and their number is related to the number of supersymmetries.

The spin-1 fields in string theory may come in many flavors. I have already mentioned the gauge fields produced by open strings with Chan-Paton factors (colors attached to the end points). But there are many other ways how string theory produces spin-1 fields. These pictures may be shown to transform into each other under various dualities and transitions.

But let's look at one more classical way how spin-1 fields may emerge from perturbative string theory: the Kaluza-Klein way. You only need a field whose one vector index is parallel to the large dimensions, to get spin-1: this index can arise from the right-moving side of a closed string. The other index, taken from the left-moving side, may be parallel to a compact dimension. That's equivalent to getting a gauge field, A_μ, from components of a higher-dimensional metric tensor, g_μ5, where 5 is a compact direction. That's nothing else than the Kaluza-Klein theory.

Instead of 5, you may also use e.g. the index 25 on the bosonic, left-moving side of the heterotic string. That also generates a Yang-Mills field. But it turns out that the gauge group in the heterotic string is neither a power of the U(1) nor the isometry of an ordinary manifold you could think about in a classical Kaluza-Klein theory. Instead, it is one of the two 496-dimensional groups, SO(32) or E8 x E8. This larger group is the extended, quantum, or "stringy" isometry of a particular chiral 16-dimensional torus used for the compactification of the 16 "redundant" dimensions on the bosonic side. Still, you can view the emergence of the gauge group in the heterotic string as a generalization of the Kaluza-Klein theory.

There are other ways how the spin-1 fields may come into existence - for example, through lower-dimensional D-branes (related to the open string's Chan-Paton factors discussed above by T-duality) or through F-theoretical singularities (related to and generalizing D7-branes). String theory includes and links all physically consistent ways how fields - including higher-spin fields - can be interacting with each other and how you can generalize this picture.

Whether we already know "everything" about this world is a different question. Of course, we don't yet know everything. But we already know something and the insights of string theory collected so far, much like the laws of mathematics themselves, are a crucial and inseparable part of it. Unfortunately, the physicists who don't know this crucial part are usually ignorant about many other, much more elementary parts of the modern physics cannon, too.

And that's the memo.

Sunday: Questioning the science of climate change

An Australian TV program (playlist, 3 parts, 22 minutes in total, click)

Jennifer Marohasy is among the global warming infidels who are interviewed and she says a couple of wise things, too.

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Incidentally, Hospodářské noviny, the Czech counterpart of the Wall Street Journal, informed about NASA's data showing H1 of 2008 as the coolest half-year in 12 years.

They have also included a poll: whom do you consider closer to the truth concerning global warming? Václav Klaus defeated Al Gore 70% vs 30%. It seems that among educated and affluent Czech readers, there is pretty much a consensus. ;-)

The article interviews Ladislav Metelka, the only Czech professional alarmist, who argues that the Sun is behind the cooling. Milan Šálek, another weather scientist, warns that we haven't seen a volcano eruption for quite some time. Its (cooling) effect would be much more significant than the greenhouse effect, he says.

Graph of the day

Gapminder: income per capita vs CO2 emissions per capita (see also PDF for 2003).

You can see that virtually all countries are very close to a particular straight line. ;-) The countries above the line are the oil-rich places that can waste oil; the countries below the line are small islands where they don't have to travel much and places with a lot of nuclear power plants.

In fact, this line doesn't even change much if you push the button and return a few decades into the past (or press "Play"). You may also see where you end up if you reduce your emissions by 80% as certain mentally unstable people - such as a former U.S. vice-president - propose.

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Global warming pseudoscientific parasites and their flatulent cows in Wales have sucked additional USD 100 million of taxpayers' money: BBC.

Black holes are politically incorrect

Benjamin has brought my attention to a hilarious story.

John Wiley Price defends his opinion that "black hole" is a racist term.

See Google News. This black commissioner is the sort of folks who are as dumb as a hoe handle and who recently began to influence the public life.



An interview...

John Wiley Price thinks that "that type of language is unacceptable". We are apparently approaching the point at which black aßholes like him will prevent us from using scientific terms such as the "black hole". (If needed, I am ready to call him a "white aßhole" because the focus is on the word "aßhole", not the word "black"!)

In fact, I predicted this story years ago which is why I have often used the term "African American hole" instead. ;-)

He asks why wasn't the term "white hole" used for such a nasty object instead of the "black hole". Well,

1. the "black hole" was chosen for a good reason that will be explained below
2. there is nothing nasty about black holes
   
3. the term "white hole" is also used, for a similar object, and the relations with black holes will also be explained in detail.

The last, third portion of my explanation will be (relatively speaking) the deepest one and I don't expect people of John Wiley Price's caliber to understand more than 5% of the ideas.

Let me start with a simple comment. "Black" is the (non)color of objects that absorb (nearly) all incoming radiation in the visible part of the spectrum. It just happens that the skin of the people of African descent is closer to black, as defined in the previous sentence, than the skin of the people of European descent.

That has a very good reason. The stronger pigmentation has evolved to protect the deeper layers of the skin from the damaging ultraviolet rays - and this protection is more important in Africa where the solar radiation is more intense. Well, these are the reasons why the people of African descent are called by words related to "black" in most languages. There exist similar rational reasons why "blackberries" and other objects have names incorporating the same adjective.

The history of the term

In 1967, John Wheeler coined the term "black hole" to describe objects that were kind of believed to exist from the 1916 paper about Einstein's general relativity written by Karl Schwarzschild and especially the 1939 paper by Robert Oppenheimer. Their gravitational field is so strong that if you fall into them, it is like if you fall into a hole and you will never escape again. In fact, not even light is fast enough to escape from their powerful gravitational grip. Because light cannot escape, the objects don't emit any radiation and they are black.

Commercial: Spiked: The rise and rise of climate blasphemy

The term "black hole" is therefore exactly what we need. It sounds good, too. And a warning for ill-informed FoxNews journalists: a singularity is surely not the same thing as a black hole! ;-)

Yes, the black holes have the same adjective "black" in them as African Americans, for a good reason. They absorb most of the incoming radiation and don't reflect (or emit) it. If John Wiley Price doesn't want to share this feature with the black holes, he should ask Michael Jackson how to proceed.

Stephen Hawking realized in 1974 that black holes emit some radiation, after all, but it is extremely weak, especially if the black holes are large. I will be mostly neglecting the Hawking radiation in the rest of this note.

There is nothing bad about black holes

Black holes in physics are vaguely analogous to various situations in reality - for example, bureaucracy has become a black hole for lost paperwork (and wasted time of humans). But in pure physics, objects such as black holes or stars don't carry any moral characteristics. There is nothing (morally) good and nothing (morally) bad about the black holes.

In fact, black holes are beautiful and important from a scientific viewpoint. Unlike certain Texan black commissioners, black holes carry the maximum information (or entropy) that one can in principle store in a given volume of space. Their properties completely govern the very high-energy, trans-Planckian scattering of other particles. They are the most natural objects that can be used to verify the consistency of theories of quantum gravity. They became one of the huge success stories of string theory.



Valleyfair attacks: a stunning story how the media have been dishonestly hiding a nasty double hate crime because the racist criminals were black, not white

Black holes and white holes

OK, so why didn't scientists use the term "white holes"? Well, white holes should be objects that tend to emit a lot of light, much like the skin of the Caucasian people, but they don't absorb it. Do they exist? In the real world, they don't. The reason is the second law of thermodynamics, the basic law of macroscopic physics that Sean Carroll completely misunderstands.

There is an inherent difference between the past and the future. If we're thinking about a thought experiment, we may begin with pretty much arbitrary initial conditions in the past. But we are not allowed to decide about the future. The future is, and has to be, whatever follows from the past by the laws of physics. There may exist objects that are "black": they are expected to emit no radiation. But there can't exist objects that are "white" in the sense that there is no radiation coming to their surface. Why? You are simply not allowed to prevent radiation from going anywhere. Some photons are always free to travel in certain directions and hit an object that you wanted to become a "white hole".

This may sound confusing to you. Can't we just apply the time reversal and switch the role of the past and the future? Well, you can do it with spacetime diagrams but it doesn't mean that such reverted histories may occur in reality. In fact, if a plausible history involves an increasing entropy, the time reverted history makes the entropy decrease which is not physically allowed.

Black holes are the highest-entropy objects we can have so this restriction should be the most important in their context: the more entropy a system produces, the more dramatic difference between the past and the future it creates. OK, so how do the rules of thermodynamics work in the presence of black holes?

Black holes and increasing entropy

Let me assume that the reader believes me that the entropy of a large black hole is proportional to the event horizon area, namely "A/4" in Planck units. Jacob Bekenstein was able to guess this relationship by general arguments applying thermodynamics to black holes; Stephen Hawking calculated it by the methods of thermodynamics from the known temperature of the Hawking radiation. Moreover, the relationship can now be calculated and confirmed directly - by counting the microstates in string theory.

Because the total entropy should never decrease, the total area of event horizons should never decrease either.

Indeed, that's correct. And in fact, this law of "increasing event horizon areas" can be derived (and was derived, by Stephen Hawking in 1970) from Einstein's equations of general relativity themselves. Imagine a typical situation. Start with two neutral black holes whose masses are M and M. The radii of the event horizons are R=2M in Planck units so the total event horizon area is twice 4.pi.(2M)^2, i.e. 32.pi.M^2.

These two black holes may merge into one object, one black hole. After some time, it stabilizes. Its mass will be 2M, the radius will be 4M, and the horizon area is 4.pi.(4M)^2 = 64.pi.M^2, more than the initial total area of the event horizons. Indeed, the total area has increased. The important thing is that this process can never occur in reverse: a neutral black hole cannot spontaneously decay into two black holes.

More precisely, such a process is possible in the context of the Hawking radiation but such "huge Hawking particles" are extremely (exponentially) unlikely. For practical purposes, it is impossible for a black hole to split into two.

The important message here is that the classical general relativity including black holes gives a geometric interpretation to the concept of entropy. And the law of increasing entropy can be proved from Einstein's equations. The reason why we can prove this law and not the inverse law is the assumption that the black hole interiors and singularities always occur in the future light cones of normal observers, not in the past light cones.

Do the white holes exist in the Hilbert space?

When you imagine a causal diagram for a star that is collapsing into a black hole and you time-revert it, to obtain a new "object" (really, it's a history) that is naturally called the "white hole", it looks completely different: the singularity is in the past while the star is in the future. The black hole is associated with some microstates in the Hilbert space. Because the causal diagram of a white hole is so different, you might think that the white hole will have to be represented by completely different microstates - because it is so "macroscopically" different.

But this conclusion is incorrect. If you try to find the time-reverted states that are associated with a white hole, you will find the very same states as those that you linked to a black hole. There are simply no other massive microstates and all massive microstates can be used as black hole microstates. It is enough for one slice through the spacetime to look similar in the black hole and white hole case to see that the microstates are "shared". We are led to a clear conclusion first articulated by Stephen Hawking in 1974:

Quantum mechanically, black holes and white holes are the same thing.

When they're the same thing, John Wiley Price could wake up and ask his question "why don't we call them white holes?" again. ;-)

Well, they correspond to the same microstates but if you actually study how they evolve in time, their history includes objects that absorb a lot of radiation but don't emit much. There is indeed an asymmetry between black holes and white holes as long as we define them by the classical causal diagrams. Black holes can exist but white holes can't. The entropy is always increasing because the past is always given by some data carrying finite information while the future is always "derived" and thus more chaotic.

In the context of black holes, this law means that the black hole singularities appear in the future, not in the past, large black holes merge and eat objects around, but they don't decay or emit objects, and this comment applies to light, too. That's why the white/black hole microstates always manifest themselves as black holes in the real world. After all, if they were white holes instead, black morons would also think it is a matter of discrimination because the famous white holes would be everywhere, they would be the key part of the Second Superstring Revolution, and black holes would be underrepresented. ;-)

Because I am not sure that this explanation will convince anyone in this crazy world, Mike Lazaridis should better rename his "BlackBerry" before it is too late. What about a "StrawBerry"? It's not perfect either. While BlackBerry is a nasty attack on a black man, StrawBerry could be an attack on a straw man. ;-)

Meanwhile, "black sheep of the family" should be renamed to a "white wolf of the family" and the "black swan" should become the "white blackbird". A subtle problem with this new notation is that the mostly black wolves are aggressive while the mostly white sheep are peaceful. (The color of devils and angels was simply copied from wolves and sheep.) It seems that Nature is racist Herself. Is it the time to destroy Her? Or is it enough to ban any talk about the color of sheep and wolves in public? :-)

Well, let's not joking about these matters too much because they are pretty serious. I agree with Mr Mayfield that anyone who is offended by the term "black hole" needs a serious psychiatric treatment. Poor Andy Strominger and Cumrun Vafa. They've been voting for junk left-wing politicians like Gore and Kerry throughout their lives and after decades, they find out that 90% of their famous papers are racist crap! ;-)

Phun: physics fun

This is a demo of an amazing program simulating mechanics that was created as a part of a master thesis. You should have it, too!

Phun home page
Phun download (Windows, Linux, Mac)
Phun YouTube group with many videos
Phunbox: sharing phunlets

Engineering hearts should be pleased.

EUR-CZK: Black swan No 23 goes mainstream

The graph above shows a function of time - between July 2007 and July 2008. Yes, it is an almost perfect decreasing linear function that may be predicted to hit zero in 2012. :-) If you look carefully in April 2008, the function includes a negative multiple of the delta function, besides a smooth component. The function suddenly dropped from 25.00 to 23.00 for a few hours (in Asian trading).

The event was labeled a black swan, a very unlikely and hard-to-predict event that sometimes influences the markets. (The name was chosen because black swans were unknown to the Europeans until they saw them in Australia of the 17th century.) It looked so crazy for a smooth quantity to suddenly jump to as unreasonably low a number as 23.



However, black swans may become pretty ordinary. In three months, namely 1 hour ago, the function dropped below 23 without any delta functions involved. Yes, it is an exchange rate - namely the number of Czech crowns per euro. If you think of the euro as a strengthening currency, you should look at the picture above to realize that your conclusion depends on the reference frame.

The euro went from CZK 29 to CZK 23 in one year which is a 20% or 25% drop, depending on what you consider 100%. The most recent 2.5-month drop of the euro from 25.2 to 23.0 is by more than 9%, corresponding to a 40% annual rate.

The dollar's motion has been more brutal. Because my reference frame was almost fully associated with the U.S. dollar until very recently, I can't tell you any details of my collapsing assets if you want to avoid a heart attack. ;-) But yes, I can tell you that USD went from CZK 44.5 sometimes in 2001 to 14.5 today - a decrease nearly by a factor of pi. Yes, it sucks. That's another reason to like the supernatural units where pi=1.

The Czech koruna has been the world's fastest strengthening currency for quite some time and indeed, there are some very good reasons behind this dynamics. The Big Mac index (assuming that McDonald's Big Mac should cost the same money everywhere, when converted by current rates) indicates that CZK is already slightly overpriced relatively to the U.S. dollar but it is still about 30% undervalued relatively to the euro - which is the main counterpart that CZK should be compared with (because it is the main currency exchanged for CZK) - so there is probably still a lot of room to go, especially if the fresh Czech GDP growth continues.

The Czech currency has also become the new ultimate safe haven currency, replacing USD and CHF.

Hendrik Lorentz: 155th birthday

Yesterday, Terence Tao and Henri Poincaré celebrated their birthdays, Congratulations, especially to the former mathematician.

Hendrik Antoon Lorentz, one of the key physicists of the end of the 19th century and the beginning of the 20th century, was born in Arnhem, the Netherlands on July 18th, 1853.

As a kid, his teachers were annoying him with classical languages. However, he was influenced by his astronomy professor, Frederik Kaiser, and became interested in maths and physics soon.

Because of this success, Hendrik later married Kaiser's niece Aletta, i.e. the daughter of the author of the first Dutch postage stamp, Johann Wilhelm Kaiser. Hendrik's and Aletta's daughter, Geertruida Luberta, became the first Dutch female physicist.

His PhD thesis was about the reflection and refraction of light. When he was 24, he became the physics department chair in Leiden. Although he was writing about mechanics, hydrodynamics (numerical calculations about dams and flood control!), thermodynamics, and solid state theory, his most important contributions were concerned with electromagnetism and light.

Lorentz was a widely admired physicist. For example, Einstein wrote the following sentence about him, among others: "For me personally he meant more than all the others I have met on my life's journey."

In 1902, he shared the Nobel prize with Pieter Zeeman for the discovery and theoretical interpretation of the Zeeman effect (the splitting of spectral lines in the magnetic field). That was a rather cheap Nobel prize for Lorentz. The correct explanation clearly requires one to understand the quantized nature of the angular momentum (and magnetic moments) that Lorentz couldn't have understood: it was decades before quantum mechanics.

Today, his classical hand-waving would be "so-so" (grade: E) as a solution to an undergraduate homework problem. In 1902, it was enough for a Nobel prize for this quantum effect and the recipient was a guy who didn't quite accept quantum mechanics until the end of his life. ;-)

There are many things named after Lorentz. One of the things that are not named after Lorentz is the Lorenz gauge - "∂_mu A^mu = 0" - which is named after Denmark's Ludvig Lorenz even though 90% of scientific papers think otherwise. Lorentz and Lorenz together discovered the Lorentz-Lorenz equation for the index of refraction as a function of molar refractivity, pressure, and temperature.

The Lorentz force is the net electromagnetic force exerted upon a charged particle, q (E+v x B), and it was first formulated outside relativity. The Lorentz distribution, associated with the function similar to 1/(1+x^2), describes the reaction of a (damped) physical system to different frequencies near a resonance. Other effects named after Lorentz, such as the Lorentz transformation or the Lorentz contraction, are related to special relativity and I will discuss them in detail.

Lorentz and relativity

Hendrik Lorentz was one of the physicists who were closest to finding special relativity but he was simply unable to crack the "complete big picture" and abandon the absolute character of simultaneity, the most regressive among the classical, pre-relativistic prejudices, even though he was already writing about "local time" as early as in 1895 and 1899.

Lorentz himself believed in "some kind of an aether" but together with Einstein, he was actually the most important physicist who helped the world to get rid of that ludicrous concept. What did he do so important? Well, he wrote "vacuum" Maxwell's equations that only included one electric vector and one magnetic vector at each point (unlike E,D,H,B of the "material" Maxwell's equations) which showed that if the aether existed, it had to be as simple as the vacuum was after 1905. ;-)

This discovery due to Lorentz was arguably the most important "recent" scientific insight that helped Einstein to discover special relativity. Recall that Einstein wasn't actively aware of the Morley-Michelson experiments: the only way to argue that he may have been passively aware of them was that Einstein referred to a paper by Lorentz where the experiments were mentioned.

And indeed, they were mentioned all over the place because Lorentz cared about these experiments a lot. In order to agree with the newest experiments, Lorentz kept on revising his edition of the "aether". For example, its length had to contract as a function of velocity and, following the early suggestions by George Francis FitzGerald, Lorentz was even able to deduce the right Lorentz factor: that's why we can call the effect Lorentz contraction even though Lorentz didn't have a crisp and modern justification of this effect (including the four-dimensional metric, for example).

Lorentz was also able to figure out that Maxwell's equations were invariant under a change of spacetime coordinates, i.e. the Lorentz transformations. Entertainingly enough, we currently use the term Lorentz group even though one of the main things Lorentz was unable to realize was that the coordinate redefinitions generated a group. Also, he couldn't figure out that these redefinitions had anything to do with the inertial reference frames in mechanics as discussed by Galileo - and that two observers in relative motion should be interpreted "democratically". Of course, any of these two realizations could (and did) abruptly lead to special relativity.

Anyway, he kept on adding seemingly bizarre but necessary effects associated with his "progressive aether" in order to avoid contradictions with the new experiments. At the very end, after a finite number of improvements, he had arguably something that was equivalent to special relativity in one particular inertial frame. But he was unable to realize that the theory was also valid in all other reference frames, even though he also knew the required Lorentz transformations that are known to be able to do the job. That also meant that he didn't have the tools to derive many other conclusions of special relativity such as the mass-energy equivalence.

This story may sound confusing and I have certain problems to understand how a leading physicist of Lorentz's caliber could have been unable to put these pieces together. And an even more puzzling fact is that after 1905, Lorentz temporarily became one of the most distinguished skeptics concerning special relativity (see a quote in the first fast comment).

But nevertheless, he was unable to do these things himself and they had to wait for Einstein who fully cracked the puzzle many years after Lorentz's aether musings. My guess is that without Einstein, special relativity would be found in less than one decade after 1905 and there would be a 50% probability that the discoverer would be from the list {Minkowski, Lorentz, Poincaré}.

Einstein chose a better strategy than Lorentz's permanent interaction with the experimenters who are often clever about minor things but intellectually limited about major issues (and who try to impose not only their hard data but also misleading interpretations upon the theorists): just sit down, go carefully through the available knowledge, and write down the correct theory of space and time from the scratch.

With Einstein's fresh mind, his approach turned out to be more successful but if you don't want to rely on such fresh minds around, I would agree that Lorentz's iterative approach was the most sensible strategy people could have followed to comprehend space and time. Still, whenever a physicist seems to be lost in a chaotic pile of seemingly unrelated laws and observations, it's good to try to return to the basics, see what insights are important and well-established, and reformulate them in new ways.

Indiana Jones IV: very good

Last night, we went to a movie theater and saw

Indiana Jones and the Kingdom of the Crystal Skull

and I think it was very good.

Warning: Spoilers are found below.

In fact, I think it was better than some previous parts of Indiana Jones - I wasn't able to finish one of them because it looked boring to me.

Different people enjoy different kinds of movies. Many people like movies that mimic the reality. Well, I, for one, hate socialist realism. I also hate soap operas that are full of average characters who damage the lives of others in hundreds of random and average ways. I don't need to watch a movie to see these things in a movie theater (or TV) again.

Your humble correspondent prefers movies (the typical "American movies", but they don't have to be made in America, of course) with well-defined, strong, and positive heroes he can identify with, movies with strong emotions and major punch lines. To some extent, I like spectacular effects and unusual events, as long as they follow a kind of logic that should be neither excessively contrived nor overly naive.

The Russian communist party recently wanted the movie to be banned as an anti-Soviet propaganda. I don't share their viewpoint. In the movie, the Soviets were slightly more negative guys than the Americans, but so were they in reality. Otherwise, the movie described a rather balanced fight of two superpowers. Were the Soviets only sending the Sputnik to outer space in the 1950s? Give me a break. There were also millions of people dying under Stalin and the movie describes a more attractive Soviet Union than it actually was. In that decade, Stalin et al. didn't do quite the same things as those in the movie but they have surely had related intentions.

OK, so what is the plot?

A Soviet unit invades a military facility in Nevada. They are led by a rather attractive yet evil woman from Ukraine: I've known such types, too. ;-) She is the personal parapsychologist of Joseph Stalin himself and they look for a special ancient magnetic skull. Indiana Jones is forced to help them (finding out that his fellow agent was bought by the Russians) but he eventually escapes.

However, he arrives to a nuclear test town and the blast comes in 30 seconds. I believe that the pictures of the nuclear blast were realistic. A few seconds before the explosion, he hides himself into a kitchen fridge. The fridge flies for a few miles and then it opens, allowing Indy to see the mushroom. Soon afterwords, he gets a shower.

Well, it wouldn't happen exactly in this way but it could have been in the ballpark of reality. I find it obvious that there exists a place near the atomic blast where you would die outside the fridge but survive inside the fridge, especially if the cavity were lead-lined. The basic idea wasn't absurd: it was just improved in order to make the effects more spectacular, and I am convinced that this is what fiction movies should be doing.

Nevertheless, some people seem to be very irritated by the scene and they began to use the term "nuke the fridge", analogous to "jump the shark". I personally think that these critics are narrow-minded people. While it might be fair to say that similar physics scenes haven't appeared in the previous parts of the series, it doesn't mean that they're "worse arts". In my opinion, they may be better arts.

If I return to the plot, Dr Indiana Jones et al. are employing careful analyses of the ancient Mayan texts to uncover some details about the mysterious extraterrestrial skull and its purpose (imagine a lot of funny car chasing, gigantic South American ants that eat people, pretty water falls, and tense interactions with Indy's ex-girlfriend Marion and a young guy who could be his son) and eventually manage to return it to a Peruvian hall (opened by a huge stony "lock" with sand) with 12 similar skulls that share consciousness.

Meanwhile, the Ukrainian bitch and her comrades also arrive there, and because the skulls want to give their saviors - including the Soviet spies - a great gift, she tells them that she wants to know "everything".

So the extraterrestrial magnetic skulls unify into one being and transfer all of their knowledge into her brain. She overheats a bit and disappears. ;-) Meanwhile, a new dimension of space in the Randall-Sundrum braneworld opens, a spaceship leaves the Earth, and the extraterrestrials cover all the traces they could have left in Peru.

At the end, Prof Indiana Jones becomes the associate dean of a college and marries Marion: and yes, the young guy he has worked with for a long time is their son, after all. Well, you might think the plot is ludicrous but it is nice to watch it!

McCain, computers, and Czechoslovakia

It's at least the third time when John McCain publicly talks about recent events in Czechoslovakia, a country that was dissolved more than 15 years ago.

The hosts pedagogically explain their wise and curious viewers that the split was analogous to the separation of Bennifer who must currently be called Jenn and Ben. ;-) Tomkat and Brangelina are doing just fine.

(By the way, Sam Nunn, a possible running mate of Obama, also thinks that there is a lot of things going on in Czechoslovakia.)

Comedians make fun out of McCain (click)

Incidentally, the Russian oil company now claims that they deliver the missing oil for Czechia (not electricity! We surely don't need it, being exporters of energy, and planning to triple our nuclear sources in 1 decade, to produce 100% of our needs by fission and to export the rest) to Turkey because of financial reasons: the radar is not the reason, they say.

Barack Obama is of course among the last ones who could criticize John McCain. For example, one year ago, Obama was loudly planning to call the president of Canada (to screw NAFTA). Even more entertainingly, he has visited 57 states of the United States of America.

That couldn't stop his fans from recording Obamian rhapsody.

A lot has been recently written about McCain's computer illiteracy, too. Well, I guess that both of these things are justifiable, related to McCain's age, and won't pose immediate problems because he should have a lot of staff that compensates for these holes.

But still, one could feel a bit awkward about McCain's reduced ability to learn new things. Reagan was also old but his hair was black. What do you think about these two (and related) manifestations of McCain's incomplete knowledge about the contemporary world?

Julian Schwinger died 14 years ago

Julian Schwinger (*1918) died 14 years ago, on July 16th, 1994. His adviser was Isidor Isaac Rabi, a Nobel prize winner. Schwinger himself shared his 1965 Nobel prize with Feynman and Tomonaga.

Four students of Schwinger received a Nobel prize, too: Glauber (in 2005), Mottelson (with Bohr's son), Sheldon Glashow (in 1979), and Walter Kohn (for chemistry: yes, the KITP Kohn Hall is named after him). Glashow's grateful memories of Schwinger are here.

Schwinger did most of his key work at Harvard University. During his life, he was affiliated with CCNY, Columbia, Berkeley, Purdue, MIT, and UCLA. He was more formal a physicist than e.g. Feynman.

Julian Schwinger liked to use Green's functions because he used to work with radars during the war. ;-) He was among the first people who have isolated the first finite one-loop correction - to the electron's anomalous moment. If you forgot the coefficient, look at his grave and you will see it is "alpha/2 pi".

The Schwinger effect is the spontaneous creation of charged particle-antiparticle pairs in an electric field. Schwinger found new and elegant proofs to the CPT theorem and the spin-statistics theorem originally due to Pauli. He found various loop corrections to certain classical identities - we call them anomalous Schwinger terms and they were essential for the development of anomalies.

The Lippmann-Schwinger equation is satisfied by the scattering states in ordinary quantum mechanics. On the other hand, the Rarita-Schwinger action is a unique action for spin 3/2 fields. The only consistent way to add interactions for these fields is to have supersymmetry: the fields then become gravitinos. Schwinger used to be sorry that he didn't spend more time with this issue because he would have surely discovered supersymmetry before others did! ;-) In fact, I find it plausible.

His personal version of low-energy effective field theory is called Schwinger's source theory. This research was criticized as boring by some of his Harvard colleagues so he left for UCLA at some moment. The ultimate proof that he was able to escape from the mainstream came after 1989 when he wrote about 8 papers about cold fusion ;-) and protested that some "conformist" bastard referees have rejected them. I would agree with him that we don't have a complete proof that there exists no complex arrangement that would allow the nuclei to tunnel through the electromagnetic barriers separating them from others - I just find it much less likely than he did.

The Schwinger model is an exactly solvable toy model for a gauge theory, a two-dimensional QED with a Dirac fermion that leads to the spontaneous U(1) symmetry breaking via a chiral condensate: the photon acquires a mass. The Schwinger parameter is the variable "x" that you integrate "exp(-xA)" over in order to get "1/A", the propagator: it emerges as the field-theoretical limit of the moduli of Riemann surfaces, i.e. the integration variables that occur in perturbative string theory.

Schwinger was the first theorist to realize that neutrinos should form doublets with charged leptons - a prediction confirmed by Leon Lederman et al. The Schwinger-Dyson equations are functional differential equations that are exactly satisfied by the correlation functions. Although this discovery and Schwinger's variational principle - a differential version of the path integral - made it possible for the fermionic integration to be uniformly incorporated into Feynman's path integral, he didn't like the path integrals - at least not openly. He described them as follows:

Like the silicon chips of more recent years, the Feynman diagram was bringing computation to the masses.

Just to be sure, when you're compared to the inventor of computer chips and connected with the masses, it's not supposed to be the best compliment you could get from Schwinger. :-) He banned the Feynman diagrams in his class. However, some people have seen Schwinger as using path integrals in the privacy. When Feynman died, Schwinger described him as

an honest man, the outstanding intuitionist of our age, and a prime example of what may lie in store for anyone who dares to follow the beat of a different drum.

I would say that it is partially a matter of social conventions who is considered to be the mainstream guy and who is the maverick. With the papers about cold fusion and complaints about the threatened academic freedom, Schwinger could be counted as a maverick, too. On the other hand, the Feynman diagrams have really become a part of the mainstream even though Schwinger's equation-based and operator-based approaches continue to have a very conservative feel to them.

Today, global warming causes...

Global warming hasn't been seen for ten years but despite the absence, it causes a lot of things. According to the mainstream media, during the last day, global warming caused

• ... 1.6 million kidney stones ("the most compelling science to date"!)
• ... malaria increase
• ... helicobacter pylori in the stomach
• ... obesity of Filipinos
• ... lower IQ (PC people won't like this one even if they like AGW)
• ... collapse of European beer
  
• ... Russians, including a dog, to abandon ice
• ... threats to water supplies in D.C.
  
• ... multiplication of pests
• ... that clean air becomes a life threat
  
• ... that Robert Redford writes poems
• ... that penises grow bigger
• ... that Utah boy becomes a hero
• ... Antarctic melting
• ... increase of floods
  
• ... that flat TV screens are deadly
• ... global cooling
  
• ... Dafur and Black Hawk down (satire)
• ... and 43,000 other things in the last month
  

Incidentally, after many years, the American Physical Society just noticed the following:

There is a considerable presence within the scientific community of people who do not agree with the IPCC conclusion that anthropogenic CO2 emissions are very probably likely to be primarily responsible for the global warming that has occurred since the Industrial Revolution.

Leon Lederman: 86th birthday

Leon Lederman was born on July 15th, 1922. Congratulations!

He is the 1988 physics Nobel prize winner for their discovery of the muon neutrino; let me neglect all other awards. Lederman was born in New York to a Russian Jewish family and did many things, becoming Fermilab's director in 1979: he is still the Director Emeritus. He coined the colorful term "God particle" for the electroweak-symmetry-breaking boson.

But I want to say a few words about their Physics First movement trying to reorganize high-school education so that kids learn chemistry and biology after they know some physics.

To some extent, this wrong system and the universities are to be blamed for the general ignorance, he says in the video below. It's terrible that even high school teachers are uncertain about maths and physics because they're pumping the same insecurity into the kids.



I am not going to be a fanatical advocate of this viewpoint but I essentially do agree with it. I used to have problems with my 300-pound high-school chemistry and biology teacher but even if I subtract this personal issue, chemistry sucked.

It contained a lot of superficial, misleading, oversimplified quantum physics that I wasn't quite ready to accept at that point: these things had to wait until the end of the high school when I really learned quantum mechanics. This limited degree of my belief reduced my interest in the subject and it looked like a lot of meaningless memorization to me.

For two decades, I haven't looked whether those hundreds of organic compounds were really necessary or useful for something. Most of them were probably not. Well, even with "physics first", there would be a lot of things that I would dislike. But it is clear that much later, I became much more excited about chemistry and biology than how I was feeling at the high school. ;-)

Even when you consider more general kinds of teenagers, "physics first" would mean that the kids understand the world "from the first principles".

It is not clear to me whether such a goal would have good practical consequences but I am convinced that in a far future, when our society becomes truly scientific, children will be taught physics before chemistry and biology because the unity of science will be appreciated and the inverse approach is really illogical. The inverse approach can only be justified by (false) assumptions about the "independence" of different scientific disciplines.

They are not independent. For sociological reasons, chemistry and biology are often studied by different tools and different people than what we call physics today but they are still parts of physics in the invariant sense.

A frequent criticism of the "Physics First" paradigm is that biology is more accessible to (typical) students who are not too good at math. Well, it is certainly more accessible to them but this fact doesn't imply that by learning biology without its origin in physics, they faithfully learn what science actually is. This "biology only" approach leads many people to think that science is about a random empirical search for statistical patterns of the type "garlic is probably good for your health" and about parroting what (other) scientists have said.

Consequently, many people become unable to understand that science can sometimes actually understand - and predict, using purely theoretical tools - the real world. That you can actually do it yourself if you learn how to do it, instead of asking Nature (or "scientific consensus") for the answer to every single question. Because of this reason, I would find it more appropriate for students to be taught a "simplified" version of the required maths and physics (where they are allowed to "memorize" various implications without knowing how to derive them mathematically) instead of the picture where the math-heavy physical basis is completely omitted.

It is plausible that children will always be taught "separate subjects" of science but the relationships between them will become much clearer than they are today. It seems that today, the authors of different textbooks etc. don't interact with each other. For most people, the boundaries between the disciplines remain shrouded in mystery. That's one of the reasons why many people approach the word "interdisciplinary" with religious feelings.

They are unsubstantiated because virtually all boundaries between scientific disciplines - e.g. between physics and chemistry - are well understood by science while the boundaries between many other pairs of disciplines are much shorter and less important than many people want to believe. The very existence (and location) of boundaries between disciplines is just a sociological convention, not a deep insight about the essence of the world.

Cargo cult science: sociology of science

Barack Hussein Obama and his wife

A new issue of New Yorker includes a story (see online abstract) about Garrett Lisi written by Benjamin Wallace-Wells. I was also asked several questions by this guy but convinced him to ask senior yet conventional physicists instead. He did it - but surprisingly, he has also asked some non-physicists. And he included a few words from your humble correspondent, too.

In the article, people generally agree that Lisi's text doesn't contain any working theory or a promising idea.

Steven Weinberg explains that string theory is being studied because it is the most attractive approach without alternatives. Well, there exist alternatives but they are worse, he says. Spencer Weart, a hard core global warming alarmist and a historian of science who believes that we live in an unprecedented era of a catastrophic warming (see his book about the "discovery" of global warming), is quoted as saying that we also live in the "slowest period" of physics in 200 years. Note that the two pieces of nonsense he likes to say are very similar. It's not shocking that the people who want to undermine the very basics of our free, capitalist, science-based, modern civilization usually like to say that our era is exceptional - exceptionally bad - and their leadership is therefore needed.

Well, we certainly don't live in any unprecedented epoch of climate change and we certainly don't live in the slowest period of physics in the last 200 years. Have you ever heard of 1810s, 1890s, 1940s and many other decades? ;-) Theoretical physics is arguably slower than in 1905 (relativity, Brownian motion, photoelectric effect), the 1920s (quantum mechanics), the 1960s (electroweak theory etc.), the early 1970s (QCD), mid 1980s (first string revolution), and mid 1990s (second string revolution), but it is still damn fast in comparison with the slowest periods.

And even if the present era were the slowest period of physics in the last two centuries, it shouldn't be a reason to abandon the scientific method. If a society decided that this would be a sufficient reason, the life expectancy of the scientific method in this society would be close to two centuries. ;-)

Most importantly, Andreas Albrecht (UC Davis), the No. 4 co-father of cosmic inflation (among other things), accurately describes the broader physics blogosphere - various types of Peter Woit, Nigel Cook, Capitalist Imperialist Pig, etc. - as follows:

... The blogs had opened physics to a new sort of populism, one that the academic establishment has to figure out how to manage. It just pushes those buttons. There's some really good stuff, but a lot of really sloppy stuff. What you have, in other words, is the erosion of the referee and the rise of a scientific underclass.

The underclass, also known as the lumpenproletariat, is defined as follows:

This scum of the depraved elements of all classes ... decayed roués, vagabonds, discharged soldiers, discharged jailbirds, escaped galley slaves, swindlers, mountebanks, lazzaroni, pickpockets, tricksters, gamblers, brothel keepers, tinkers, beggars, the dangerous class, the social scum, that passively rotting mass thrown off by the lowest layers of the old society.

If you are afraid that the quote above was written by an angry far-right ideologue, you should calm down because this definition comes from the angry Karl Marx himself. ;-) He actually hated the underclass - in his optics, it was sharply separated from the working class - not because it was mostly scum but because the underclass had helped to bourgeoisie and Napoleon, the real villains! ;-) As a result, his description sounds as accurate as if he had visited the threads at Not Even Wrong.

Of course, Albrecht is quite correct that the underclass is fundamentally incompatible with the traditionally organized scientific process because it wants to circumvent any kind of quality control - including the conventional, meticulous referees etc. - and turn to the "heat bath" of loud low-quality mobs for guidance. Instead of referees who are very careful about their scientific "credit score", they want lumpenproletarian critics who have nothing (no credit) to lose but their chains. ;-)

What is being planned by the scientific underclass is a new counterpart of a communist revolution, even though its impact should be limited to the realm of science.



Here I discuss an annoyingly serious topic but the video above is the most entertaining physics populist video I have ever seen. You can't avoid laughter because this crackpot with his youstupidrelativist.com website is so perfectly honest. He simply can't even pretend that his IQ is above 70 but nevertheless, he has literally nailed Leonard Susskind down (using my picture, too)! :-) And there are at least 7 parts of Einstein's idiots. Enjoy.

It remains to be seen whether the underclass will pose a threat to the whole system - much like it has been an extremely harmful threat for your humble correspondent. Believe me, if you don't live in your ivory tower, isolated from the real world, it is a risk for your life to even suggest that the underclass is fundamentally misguided. Maybe the underclass will threaten the towers, maybe it won't.

The traditional underclasses have ceased to be a threat for the developed nations because the functioning capitalism has made almost everyone richer - something that Karl Marx wasn't able to predict. Let's hope that the scientific underclass will become equally harmless because virtually everyone will get educated in the future and sloppy, stupid, superficial, hateful, populist blogs such as Not Even Wrong will simply lose all of their audiences (we are on the right track - Woit currently runs at 40% of the TRF capacity or so - but we are not quite there yet). Meanwhile, one third of the world may be controlled by the scientific proletariat for one century, before this regime is shown to be unviable.

Let me give you a superficially innocent example of the dramatic incompatibility of the scientific underclass and the conventional scientific process.

Sabine Hossenfelder wrote another activist text promoting the idea that science - the very selection of correct and promising ideas and research programs - should be controlled by social criteria and by the bureaucrats.

She promotes her favorite ideology that the markets, especially the markets of ideas, are imperfect - and even the advertisements (a tool to spread the information about products whose fairness increases with the frequency and the related consumers' ability to evaluate the information rationally) make the markets break down - but concerning her attitude to the quality control in the scientific process, this quote is particularly telling:

I am just a physicist who has had too much time thinking how the academic system sucks, wondering why nobody in it seems to listen to what the sociologists say, and why said sociologists don't come up with practical advices (interdisciplinary research, anybody?).

Well, it sucks but exactly for the opposite reason than she proposes: the Academia is beginning to be driven not by merit but by the social goals of the scientific lumpenproletariat. Concerning her question: if she's wondering about it so much, why hasn't she simply asked it?

The answer is obvious. Scientists don't listen to sociologists not only because sociologists' IQ is lower by 15 points in average - one full standard deviation - but, more importantly, because sociology as a tool to choose scientific ideas and research programs is a pseudoscience. Galileo Galilei was one of the first men - but probably not the very first man - who understood that the scientific ideas should not be selected if they look nice to the Pope or to the underclass but if they imply, directly or indirectly, predictions that happen to be confirmed by observations - or at least, if they're closer to this goal than the competing ideas.

Even her very title, "We have only ourselves to judge on each other", shows how flagrantly incompatible with the essence of the scientific method her thinking really is. In science, not only we have other things besides "ourselves" to judge: I mean Nature, the ultimate objective judge. Nature is, in fact, the only player who can really judge the scientists' ideas as long as they behave as scientists. She can't speak "directly" but Her effective spokespeople are Her boyfriends - the Gentlemen and Ladies who have been most successful in having an intimate relationship with Her. And there's a huge hierarchy in this business.

Sorry to say but Sabine Hossenfelder, Garrett Lisi, and their loop quantum gravity friends are extremely far from this category of Nature's boyfriends if you compare them e.g. to Steven Weinberg. Tommaso Dorigo is not a boyfriend of Nature either, at least not now: in fact, he refers to Her as the bitch, a term that doesn't indicate that he finds himself in too intimate a contact with Her himself, even though many others do. ;-) To make things worse, Hossenfelder mentions an anonymous physicist (it could be someone like Stephon Alexander?) who decided to switch to loop quantum gravity and uses this sad episode from the underclass to argue that "there is change knocking on the front door." Oh, really?

Does your anonymous friend also plan to knock on Steven Weinberg's front door in Austin, Texas and tell him that he should change himself and study (or at least promote) loop quantum gravity, too? They should better check up their Texan handguns!

After years of heavy interactions with people as stupid, as aggressive, and as arrogant as herself, i.e. with the underclass, has Ms Hossenfelder completely lost her mind? I don't know how to explain these matters comprehensibly enough but let me try again: relatively to real top physicists, they are just a tiny piece of a waste product of metabolism who often got into the system mainly because of quotas on the female reproductive organs and other things. Whether they would like a certain kind of change is completely irrelevant.

None of them can reach to Steven Weinberg's ankles. Do they really want to dictate him and his peers how he should change his opinions about physics so that it better suits their tastes and personal interests? Everyone who is buying into the idea that "there is change knocking on the front door" of the type advertised by catastrophic left-wing activists who say that we live in an "exceptional era", an era of the "end of science", and so on belongs to the lumperproletariat himself.

There is no change like that knocking on the door and there is no justification for such a change.

To make us really sure that she also belongs to the moral underclass, Hossenfelder informs us that the activity in science focuses on theories where "money and attention go". Wow. Corrupt pseudoscientists may be choosing their interests - and maybe even their beliefs about the actual statements in science - according to the flow of money to their pocket (which is why there are so many pseudoscientists behind the "climate consensus" these days) but the scientists who actually deserve the name honestly look at objective criteria instead. I don't claim that scientists motivated by money can't ever contribute substantial things but I want to claim that those whom I consider to be the real leaders are unaffected by financial and similar pressures.

Richard Feynman described the pseudoscientific nature of sociology nicely in his famous 1974 Caltech commencement speech. Once he told the students some cute stories about the picking of beautiful chicks in paranormal baths, about Uri Geller's tricks, and other crazy things that many people believe, he continued:

... But then I began to think, what else is there that we believe? (And I thought then about the witch doctors, and how easy it would have been to check on them by noticing that nothing really worked.) So I found things that even more people believe, such as that we have some knowledge of how to educate. There are big schools of reading methods and mathematics methods, and so forth, but if you notice, you'll see the reading scores keep going down - or hardly going up - in spite of the fact that we continually use these same people to improve the methods. There's a witch doctor remedy that doesn't work. It ought to be looked into; how do they know that their method should work? Another example is how to treat criminals. We obviously have made no progress - lots of theory, but no progress - in decreasing the amount of crime by the method that we use to handle criminals.

Yet these things are said to be scientific. We study them. And I think ordinary people with commonsense ideas are intimidated by this pseudoscience. A teacher who has some good idea of how to teach her children to read is forced by the school system to do it some other way - or is even fooled by the school system into thinking that her method is not necessarily a good one. Or a parent of bad boys, after disciplining them in one way or another, feels guilty for the rest of her life because she didn't do "the right thing", according to the experts.

So we really ought to look into theories that don't work, and science that isn't science.

I think the educational and psychological studies I mentioned are examples of what I would like to call cargo cult science. In the South Seas there is a cargo cult of people...

Sabine Hossenfelder's musings are the ultimate incarnation of this cargo cult science that doesn't work because its predictions are never being tested by the scientific method. She wants to put mobs and sociologists (including the amateur ones, such as herself - she reveals that she has even applied for a grant to be paid for pretty much the same sociological conspiracy junk she is writing on her blog: fortunately, the application was rejected because she was an amateur) not only above the high school teachers but above the scientists themselves!

No, it won't work. The selection in science works and has to work very differently from the way envisioned by Lee Smolin and the scientific lumpenproletariat. Lee, feel free to brainwash the stupid people with populist clichés. And stupid people, feel free to believe manipulators like Lee Smolin. But unless things start to collapse, both of you will remain irrelevant for the actual science as we know it.

And that's the memo.

Ammonia: Proton-electron mass ratio constant for 6 gigayears

In 2006, a Dutch team (Ubachs et al.) measured the Hydrogen spectrum emitted 12 billion years ago and concluded that the proton-electron mass ratio - currently close to 1836.15 - used to be 1.00002 times higher than it is today!

I have always believed that the experiment had to be wrong because the constants (not only the mass ratio but also other functions of the low-energy parameters of the Standard Model) have no good reason to evolve. Moreover, it is very unnatural for the change during 90% of the universe's lifetime to be 20 parts per million only but not zero.

Most likely, the moduli have been stabilized since the very early moments after the Big Bang. Assuming otherwise would lead to all kinds of bizarre predictions, including new long-range forces or new phase transitions that could spoil the Big Bang cosmology or gradually destroy life by modifications of the binding energies of DNA bases. I simply don't buy such an evolution and I don't think that such an evolution really helps to solve the cosmological constant problem or anything of the sort (moreover, quintessence seems highly disfavored observationally).

Many journalists (and physicists!) occasionally use the term "string theory" when they mention their speculations about evolving constants of Nature. But it is important to know that every single universe from the proverbial "landscape" of 10^{500} or so solutions predicts that the constants are fixed forever. In canonical string theory, these constants don't evolve.

That's true almost by definition because the number counts the stabilized vacua. There could also exist semi-realistic non-stabilized vacua where the constants evolve but they seem to have problems, they are not terribly well understood, and most of the "good" physicists (this adjective shouldn't be interpreted too dogmatically) don't believe that they are relevant. We could still be wrong but it seems misleading to use the term "string theory" to support the speculations about evolving constants because string theory, as understood today, works differently and much more rigidly.

Back to 2008

Now, USA TODAY informs about a new experiment by Christian Henkel et al. (Bonn, Germany) that looked at ammonia molecules 6 billion years into the past.

Do you remember the Feynman lectures in physics, namely the chapter where quantum two-level systems are discussed?

The ammonia molecule has a nitrogen atom right above the center of the triangle of hydrogen atoms. The energy eigenstates are the sum and/or the difference of the quantum states where the nitrogen is above and/or beneath the triangle. And very low frequency photons can be emitted in between these two states. The frequency turns out to sensitively depend on the proton-electron mass ratio.

See their original paper in Science from June 2008:

Strong limit on a variable proton-to-electron mass ratio from molecules in the distant universe (full preprint plus a press release)

During the last 6 billion years, the ratio has changed, relatively speaking, by less than 2 parts per million (ppm) at the 95% confidence level, much less than the alleged Dutch positive signal that was claimed to be 20 parts per million.

Whenever there are two experiments and one of them gets an agreement and the other one gets disagreement, I think that it is much more likely that the experiment showing a disagreement is incorrect because it is much easier to introduce an error (any error) that destroys the agreement than to keep all things pure and accurate so that the agreement is preserved. ;-) In other words, it is unlikely to get an accurate agreement by chance.

Of course, the Dutch team has looked into a more distant past (something could have, in principle, happened when the Universe was between 1 and 8 billions years of age) and it has studied a different molecule (that could, in principle, lead to different results than the ammonia molecule). But I find all these explanations unlikely. The most plausible explanation is that the Dutch experiment was simply wrong. It would be nice if someone could locate the mistake more accurately.

If you believe the new paper, it might be the best bound available on the market.

LHC doomsday: humor

The LHC has been mostly cooled down. The temperatures in sectors 23, 34, 45, 56 are around 2 K while 67 has 2.5 K, 78 and 81 (next to LHCb from both sides) have around 18 K, and 12 has again around 2.5 K. 



Recently there have been several funny stories in the media about the LHC doom:

• Paris Hilton starts the LHC collider
• LHC test run swallows a Swiss village
• LHC ready to test condom mechanics
• LHC doomsday imminent
• LHC may destroy universe, say stupid people

As a bonus, the last story is almost 100% accurate. ;-)

See also a funny picture about the LHC, the CMS stop button, or click the "lhc" category in "other texts" below for dozens of LHC articles.

Happy Bastille Day

It's been 219 years since seven criminals were allowed to escape from a prison in the Kingdom of France. ;-) The following events turned out to be rather hectic. At any rate, congratulations to the French readers!

Predicting Barack Obama

As various outlets including MSNBC pointed out, Barack Obama is moving to the political center.

According to some criteria, Obama's voting record has been the most liberal one among all U.S. senators (in 2007, and also previously). On the other hand, as far as I remember, he has never made me really upset, unlike most left-wingers who have appeared in the media (or the blogosphere or my real life).

I generally believe that most of the blacks, including the educated ones, don't buy into political correctness - at least when it comes to "sexism" i.e. the rudimentary knowledge about the differences between men and women. And he also has the Christian background.

Recently, he has been moving to the middle. Of course, he is now fighting for a different voter - the U.S. voter rather than the Democratic voter - so this whole approach could be a part of his personal strategy. His highly left-wing voting record could have been a matter of strategy, too, one designed to win the party nomination. The policies he has endorsed lately include

• intelligence surveillance bill (a compromise)
  
• North American Free Trade Agreement (at least softened his anti-trade rhetoric)
• handguns (he was against a D.C. ban)
• death penalty for child rape (Obama criticized a high court that opposed it)

And in two weeks, he even wants to follow Ronald Reagan - whom Obama has repeatedly praised - and scream "tear down this wall" in the same place of Berlin. (Too late, Barack, the wall is already gone! By the way, see some Reagan humor.)

When you take all these and other things into account, you may crystallize your own forecasts and participate in the poll below.

Smartkit: Poiser game

Poiser: a hand drawn physics puzzle game

Full screen (click)

In this game, you have to place a sufficient number of boxes on a seesaw so that you surpass a critical line. The boxes follow the laws of classical mechanics. Starting from the third level, they come in different sizes. Good luck.