NYU about Hořava-Lifshitz gravity

Keith Chen (click) wrote a rather illuminating story about the fate of Hořava-Lifshitz gravity (click and read this text first!) at the NYU.

Journal clubs are apparently alive and well over there. I think that they're important for the health of science as seen from a broader scientific community's viewpoint. I found the "[postdoc] journal club" to be one of the most satisfactory formats for creative scientific confrontation. All ideas and criticisms by sensible and quasi-sensible people can be raised. They can be debunked, too.

Andrei Gruzinov, a professor of theoretical astrophysics, wanted this paper (or these papers) to be analyzed - because of those "cool properties" that have been said about it (including its being a theory of quantum gravity and a replacement for inflation), mostly in dozens of Asian preprints. Andrei Gruzinov asked Matt Kleban to present the paper in the journal club.

Their analysis focused on the question whether the heavily nonrelativistic "z=3" theory in the ultraviolet can flow to the relativistic "z=1" theory in the infrared. See also a later article,

Can Hořava gravity flow to Einstein gravity?

Massimo Porrati gave some arguments why it was not possible. Incidentally, although he hadn't read the whole paper(s), Porrati claimed that if the paper were right, he would switch his field to swine flu. ;-) At the end, the previously excited people considered the attempt to be a failed one and they have lost interest in it.

So did I. Let me summarize the main problems:

• in the IR, normal GR should be reproduced; but this effective field theory needs all the spacetime diffeomorphisms to be gauged, in order to eliminate all unphysical polarizations of the waves; because the spacetime diffeomorphisms are broken, one can't get rid of all the unphysical states; after this blog article was written, a paper by Charmousis et al. was released; it explains the appearance of this unwanted (and strongly coupled) mode at long distances in detail (the second, more serious problem they find); the experiments indirectly observing gravitational waves etc. seem to rule out Hořava's theory
• it is questionable whether the very qualitative flow from "z=3" to "z=1" is possible, starting from a small perturbative deformation in the ultraviolet
• even if it were possible, one would need a huge amount of fine-tuning to restore the Lorentz symmetry in the IR (so strongly constrained by the observations), especially once all the matter fields are added
• the Lorentz symmetry violation in GR leads to many likely inconsistencies, including the possibility to construct perpetuum mobile gadgets of the second kind, at least in principle
• even the very scale invariance of the hypothetical UV theory doesn't seem to have been demonstrated beyond the classical level
• in the fast comments, it is argued that the correct, ordinary black holes with an area-extensive entropy probably can't be created in this theory; local theories like this one probably always predict a volume-extensive entropy; near the would-be event horizons, the deviations of Hořava's theory from GR are probably huge (e.g. Lorentz violations get amplified) and prevent the normal black holes from creation

In my opinion, these are big problems and every single one of them would be enough to kill my interest in a theory. Their combination is even more lethal. If you have something really substantial to say about those technical problems, you're welcome.

Philosophy of science

Meanwhile, I want to say some important things about the philosophy and sociology. I find the "postmodern" opinions of many young people, including those whom I don't find personally unpleasant, extremely worrisome. These attitudes are doubly sad if they appear at NYU, a place that Alan Sokal transformed into a bastion of the war against the postmodern nonsense. For example, Keith writes:

So it was pretty funny that last week everybody was excited about this paper and this week everybody loses interest in it. We have to wait for another breakthrough.

Well, this is how science works. We can never be sure that we're right: we can only be sure if we're wrong. Theories are being abandoned once they disagree with some aspects of the observations. That's what has apparently happened with this attempt, too. The theories that matter are those that can survive some tests - for some time that can be either long or very long. At the end, more demanding experiments find some problems, too (with the final theory of everything being the only possible exception).

Indeed, it often takes a two-hour journal club to settle such things and kill a hypothesis. Two hours is not a microscopic amount of time. That's because Petr Hořava is a thoughtful physicist. Similarly ambitious, average papers written by less thoughtful physicists than Petr take about 5 minutes to be killed - or 4 minutes, ask Lee Glub Glub Glub Smolin at the bottom of the sea for the most up-to-date timing. :-)

Keith adds a few comments:

Nobody really knows how to come up a workable quantum theory of gravity.

This sentence reveals Keith's complete misunderstanding of the last 35 years (OK, 34.5) in theoretical high-energy physics. But let's focus on the philosophy here:

So anybody can take strong opinion in this regard. But anybody that asks the right question is much much more likely to succeed than others.

Except that the journal club has led to the conclusion that the right questions have not been asked in this paper. "Right questions" are not the same things as "any questions" - despite the fact that Keith, as a skillful propagandist, composed his sentence in such a way that it is almost impolite to point out an obvious fact such as the beginning of this sentence. ;-)

Well, I don't find it impolite. Quite on the contrary: I think it is essential for scientists not to be manipulated by rhetorical exercises of others into fear to point out the obvious.

But shouldn't it be obvious that anything that is obvious is not going to work. Anything that is going to work is not going to be obvious.

Well, more precisely, anything that is going to succeed in the future is going to be slightly or very different from the things that have been tried and that have failed in the past. The previous sentence is a tautology.

But whether the new things will be obvious depends on a subjective judgement. For example, I think that the Hořava-Lifshitz Lagrangian - or any similar Lorentz-violating attempt to circumvent the failures of Lorentz-invariant local field theories of gravity - is obvious. The only problem is that it seems to be wrong, too.

Whether or not things look "obvious" to you depends on your definition of "obvious" and your emotions, education, and experience. The discoverers usually find their ideas more "obvious" than others. Moreover, the more experienced the other people will become, the more "obvious" those theories will look to them. But that's not what science is all about. Science is about hypotheses' being right or wrong, not about hypotheses' being "obvious". The latter should be left to the educators who decide how much time they should spend with XY at schools - or to the journalists who try to hype some mind-boggling results. It has nothing to do with the scientific research.

But Keith's ideas get much worse:

The reason that those smart people fail to come up with a sensible theory of quantum gravity maybe because they are too strongly biased. I defend this theory does not mean that I believe that this the right theory.

Again, the statement that we don't know the right theory of quantum gravity is a misunderstanding of the last 35 years in theoretical high-energy physics. But the philosophical background behind the two sentences is even sicker.

In science, it is simply not possible to defend a hypothesis or a statement without rational arguments. You may feel compassionate when hypotheses are being killed just like cars that are being made in Henry Ford's flow production (or even in Chrysler that is just sadly filing Chapter 11). But you're not acting as a scientist if you allow these emotions to influence your decisions because the falsification of hypotheses is the most basic and most paramount among all tools that science uses and has to use.

In science, one shouldn't really defend theories against falsification. And one shouldn't defend theories that he believes to be incorrect (because of rational reasons), either. The closest thing one can do is to show that the would-be falsification is actually incorrect (or at least less complete or less certain than previously thought). For example, chiral superstring theories were believed to be dead in the early 1980s because they were thought to be spoiled by anomalies.

Green and Schwarz believed otherwise. But they actually had to make very extensive, detailed calculations showing that the "incomplete" proof of the nonzero anomalies (accepted by most physicists in the field) was actually incorrect and that all the anomalies canceled when calculated exactly. Without this result, the first superstring revolution of 1984 couldn't have taken place. And indeed, it would have been profoundly irrational to switch to a theory that was believed, for pretty good (but not quite good) reasons, to be anomalous. You know, it doesn't matter how beautiful a theory is or what the name of the author is.

The calculation of the anomaly cancellation was no detail. It was one of the key results deciding whether the theory was right or wrong. And by all these criteria (and according to hundreds of other tests that have been successfully made between 1984 and 2009), superstring theory turned out to be right, at the end. But if you have a "similar" hypothesis without such an anomaly cancellation - an argument showing that the "falsification" is actually incorrect - you simply can't assume that the cancellation is a "formality". It's not. A hypothesis is dead unless and until a mistake is found in the falsification.

In our postmodern reality, some people are even bothered by the fact that "ideas of a certain type" are constantly being falsified and abandoned. This type of compassion is even worse because what they consider "sad injustice and discrimination" is called "general results and general insights" in science. And they are actually a very good thing!

Scientists have made many mistakes in the past. While many of them failed to appreciate the principles and methods they should have learned, many others have been way too dogmatic. They didn't want to listen to a certain new type of evidence. They often needed a much longer time to accept a new, demonstrably better theory than the time that the ideal scientists would have needed.

Geologists needed decades to accept Wegener's crisp arguments in favor of the continental drift. Some physicists have needed (and, indeed, will need) decades and thousands of failed "alternative" attempts to understand why string theory is inevitable in the context of quantum gravity. But despite all the scientists' imperfections, it must still be rational arguments - sometimes more extensive and accurate arguments than the ideal scientists would find necessary - that can change the ideal scientists' opinions as well as the real scientists' opinions.

If a scientist needs too much time to understand a new theory - and why it is better than the old one - he is an imperfect scientist. But if he is generally deciding according to emotional rather than rational criteria, or according to quotas rather than calculations and observations, he is not a scientist at all. That's much worse. Imperfections slow science down but they are largely inevitable given the finite intelligence and limited integrity of the humans. However, dominant emotional criteria kill science.

Everyone who wants to fill science with emotional arguments and criteria that should have the same impact as technical arguments - but these technical arguments actually don't exist - is killing science and replacing it with politics and superstitions. Just like the real market imperfections can't be "cured" by communism, the imperfections of the "market of ideas" can't be cured by the postmodern feminist pseudoscience. The only thing that these "cures" can do is to kill the prosperity and/or science.

So what Keith calls "bias" is actually nothing else than the scientific integrity itself. Keith adds:

OK, Hořava did not lay out the model in details.

Well, I actually think that he did. He has made something that is close to the best possible case for this idea. That's also the main reason why Petr's original papers are more widely cited than any of their followups.

But I think he has set up a proposal that is interesting enough to pursue it further.

This is exactly what the NYU professors did, isn't it? This is why they ordered Matt Kleban to present the paper in the journal club. Keith Chen may dislike the outcome. But in science, what matters are the correct outcomes, not outcomes that someone likes.

And one simply cannot write papers with pre-determined "signs" of the results. More precisely, Keith (or the authors in Beijing) may be motivated (and is free) to write "revolting" papers of a certain kind - but whether or not such a "revolt" has actually led anywhere must be decided by the scientific criteria again, not by unfairly pre-determined labels of "bias" and "worthy research" reserved for results with particular "signs". And whoever cares about "revolts" more than he cares about rational arguments is likely to produce random gibberish, at least in the long run.

One of the reason that so many people have jumped into this theory because they think that it is interesting and worth trying.

This sentence shows Keith's inherent inconsistency and bias. When it comes to the NYU people, he thinks that their opinions are "biased" and something is wrong with the sociology: people can't be trusted. But when it comes to some Asian authors of not-quite-penetrating followup papers, Keith decides to praise them and to repeat some uncritical hype. Where does the different attitude come from, Keith?

So my philosophy to these kind of difficult open questions is that we should keep mind opened.

Well, the disadvantage of replacing science with an "open-mind philosophy" is that you won't be able to do any science - because every scientific result and every event in science that matters is closing a small hole in the mind (and, sometimes, opening new holes in a piece of mind that was previously unknown). Every result is filling a hole in our Swiss cheese of knowledge and ignorance. Being constantly open-minded about everything is exactly equivalent to the ban on any progress in science, Keith. Opening one's mind entirely also makes it possible for the mind to completely evaporate. ;-)

"Fortunately" for Keith, it's not what he's doing. He's keeping his mind about many key issues - such as our knowledge of a consistent theory of quantum gravity - hermetically closed: he has only been closing the holes according to very different criteria than the rational, technical arguments that his senior colleagues at NYU prefer and that science is based upon.

And that's the memo.

French germophobia rejected: so far

Nikola Tesla, Michael Jackson, and Cameron Diaz are among the most famous people who have suffered from germophobia.



The French nation has just collectively joined the group. Yes, it is a very paradoxical decision. ;-) We are talking about the same French nation that has invented (or re-invented, following Kamasutra) exercises such as one on the picture above. When I was in Paris a year ago, I had to kiss 38 women a day in average. :-)

Nevertheless, France has asked the EU to suspend flights between Mexico and the whole EU. Wow. The Czech EU presidency and European Commission thankfully rejected these calls. That's good news because the French minister of health, Ms Roselyne Bachelot, despite being a doctor of pharmacy, is demonstrably an epidemiological crackpot.

By the way, a crew of Air France managed to impose the ban on their aircraft: these striking sissies have simply rejected to fly to Mexico. ;-)

But let's return to the big picture.

One simply can't quite isolate Europe away from Central America. Some "essential flights" would have to occur, anyway. Moreover, the swine flu virus has already spread to Europe, too. It is impossible to effectively determine who is infected because many infected people don't exhibit any symptoms. As Sheldon Cooper (who is a germaphobe himself) correctly emphasized in The Big Bang Theory, if the symptoms had always accompanied the disease, the disease would have already died a long time ago.

Most importantly, it seems very likely that non-Hispanic people are pretty much unaffected by the virus. All casualties, including one on the U.S. territory, have been (genetically) Mexicans. We can speculate whether this special sensitivity of the Mexicans is purely genetic in origin or whether it is affected by their reduced immunity due to their less luxurious lifestyle or polluted environment: my guess is the former.

If you think that the main reason is the habit of Mexicans not to visit conventional doctors, choose either "culture and lifestyle" if you think that the reason behind their behavior is psychological or "poverty" if it is economic. People who agree with Orson that the reason is that the Mexicans are not vaccinated against similar flus, unlike the Yankees, choose "reduced immunity due to poverty". But I assure you that other, richer nations are not obsessed with flu vaccines, either.

But trying to isolate our continent from a country that is as important as Mexico would be far too expensive. An influenza virus managed to mutate and it is destined to kill a few more people. The virus deserves it for its achievements. The idea that we can and we should save absolutely everyone, whatever it costs, is a proof of germophobia by itself.

We must simply deal with it. So far, the disease is far less important for the public health (and even for the number of people who die) than ordinary flu. It may stay so. Anti-viral drugs may be effective and a vaccine may be found, too. At any rate, attempts to isolate whole countries could only delay the propagation of the virus by a few weeks - while the costs would be huge.

North Pole: ice 100% thicker than expected

Radio Bremen (in German), April 28th, 2009
... (automatic translation to English)

Surprising results

In Canada, "Polar 5", a research aircraft (see 27 hi-res pictures), has ended its recent Arctic expedition today. During the flight, scientists were measuring the ice thickness in regions that have never been overflown before. The result: the sea ice is apparently thicker than the scientists had suspected.

Under normal conditions, the ice is formed within two years and ends up being slightly above 2 meters of thickness. "Here, the thickness was as high as four meters," said the spokesperson for the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven. According to the scientists, this conclusion seems to contradict the warming of the ocean water.



Besides the thickness of ice, the expedition has also investigated the composition of the air. Lasers were used to study the air pollution by emissions from various countries. Within weeks, the results will be evaluated. About 20 scientists from the U.S., Canada, Italy, and Germany participated in the project.

[Well, I guess that you won't hear about this experiment from the journalistic suidae. LM]

Translation from German: LM

Pen Hadow et al.

The resupply still seems very hard. The Catlin Arctic Survey team - that is trying to achieve more modest scientific results than "Polar 5" but with a stronger psychological, religious experience - is already used to food rationing, so another wave of it is no big deal. Moreover, Ann Daniels, a mother of four, has a hoodie that she uses to cry in solitude. That allows her to continue with the (other) religious bigots.

They have lived through a big storm and reduced 6,000 calories per day down to 1,000 calories so that they can survive for a week. Their collaborators will try to send the aircraft again tomorrow, before another storm that will return on Thursday and Friday. The airplane requires clear skies at 7 locations or so (because of refueling etc.).

Vista Service Pack 2 final

Microsoft has finally released (KB 948465) the final RTM version of SP2 for Windows Vista and Windows Server 2008 (see Windows Team Blog): as confirmed at KB 955430 (which you should have installed before the service pack), the build number is 6002.18005 i.e. 6.0.6002.18005 (090410.1830). Links to torrents that contain everything you need in any language edition you may have: 32-bit edition (498,781,016 bytes), 64-bit edition (700+ megabytes). Half an hour of installation. See a screenshot with some additional numbers and codes identifying the version.

The Vegas Renormalization

Episode 2x21 of The Big Bang Theory:

Watch it at Supernova Tube (click)

Abstract: the hormonal system of the loop quantum gravity bitch, Leslie Winkle, collapses again - so she dumps poor Howard. ;-)

Las Vegas is the chosen place for him to get rid of the divergent and other loops and to get renormalized. Meanwhile, Sheldon's nearly realistic dreams about solitude are destroyed by a missing key: Penny's horny dreams get more realistic instead. :-)



Click to zoom in. See the previous speedometer anniversary.

While Penny has to undergo an annoying interrogation about sex and emotions by Sheldon, Leonard and Rajesh buy a Jewish girlfriend experience for Howard. :-) Howard is able to determine that she is a prostitute - and he thanks his friends. Sheldon receives Penny's bed for a night, without her, but with her brand new singing of Soft Kitty.

I am often afraid that the producers have overshot Sheldon's asexuality, bringing it to irreversible dimensions. But once again, everything is possible on TV screens.

Czech dubbing

I have just watched the episode 1x04 in Czech dubbing, as created for Czech Prima Cool TV. It was the first episode that I enjoyed more in Czech than I did in the original version. Sheldon's Czech finally became formally perfect and many other "details" have been fine-tuned, too. Good that I didn't abandon their work prematurely.

F-theory bottom-up uprising: CP3 blowups

The F-theory phenomenological minirevolution is going on. Joseph Marsano, Natalia Saulina, and Sakura Schafer-Nameki (Caltech) wrote a 55-page paper called

F-theory compactifications for supersymmetric GUTs (PDF)

that constructs very explicit Calabi-Yau four-folds that produce SU(5) grand unified theories if used as backgrounds for F-theory.

As the final picture for the base manifold, including the diamond E' in the middle, indicates, they obtain the space by a sequence of blowups and flops, starting from CP3. Recall that CP3 is a toric geometry with a simplex as its toric diagram: you find it in the paper, too. Many of the world's best geometers below 40 were helping them to understand the manifolds.

In my opinion, the complex projective space is the most natural starting point for local constructions because among complex geometries, it is the simplest compact approximation of the flat space. However, a couple of operations have to be performed for the consistency conditions to be obeyed.

They find out that the conditions for viable phenomenological features - such as three generations with hierarchical masses, the unbroken U(1) hypercharge, and the main principle behind the botttom-up phenomenology (decoupling of Planck and GUT physics) - arise naturally in these constructions. They're the first professionals who write a full-quality paper that takes Donagi-Wijnholt as well as Beasley-Heckman-Vafa papers into account.

Donagi and Wijnholt actually performed a more complete local & global analysis than Vafa et al. - which might be used as a simple description of the apparent limited degree of interactions between those two teams and the marginal contradictions between their papers - and Marsano et al. may be going even further in the accuracy of their analysis. These backgrounds really exist, they're nice, and they're simple.

Heterotic strings used to be the most natural and likely realizations of the real world within string theory. Many of the F-theory constructions in these minirevolutionary papers have heterotic duals but the most phenomenologically promising F-theoretical bottom-up vacua actually don't admit conventional heterotic duals at all.

Concerning the diversity discussions, this perfectionist paper has quite a diverse collection of authors. One author is a woman (privet, NS!). Another author belongs to an even more special group: she is a woman of color. But that's nothing compared to the third author who is a conservative in the Academia (hi, Joe!). ;-)

Some other papers

By the way, Asia is getting mad about the Hořava-Lifshitz Lorentz-breaking UV-complete general relativity. Today, there are three hep-th papers about this topic. Sorry but I won't declare the situation another minirevolution because at least so far, I view this framework as unmotivated.

Media: swine flu beats global warming

According to Google News, there are 24,000 articles in the last 30 days that talk about swine flu, surpassing 24,000 articles about global warming. One day later, swine flu articles doubled to 50,000+.



Warning: this cartoon is irrational because you can't get infected by eating pork.

Swine flu makes some sense as a threat. It is actually killing people and pandemics have occurred many times. However, empty threats have been frequent, too. Bird flu has arguably been an overhyped threat, too: only 257 out of 421 infected people were defeated by avian flu. What do you think about the number of people who will be killed by swine flu by the end of 2009?

Also, see another poll why the flu only kills Mexicans - in the article French germophobia rejected.

So far, only 149 people have died and all of them lived in Mexico. (Today in the afternoon, Mexico City was hit by a 5.6 earthquake, too.) Moreover, it is conceivable that anti-viral drugs will work against the disease.

However, don't be afraid of high figures if you intuitively find them expectable (I don't): the Spanish flu pandemic (1918-1920) has killed 40 million people and millions of people died around 1957 and 1968, too.

The previous poll was one about the success of Pen Hadow's Arctic expedition to the North Pole. By the way, the resupply failed today due to low cloud cover. The explorers may face 36 hours of a huge storm, possibly bringing them closer to the ultimate sacrifice.

By the way, the story about swine flu is only the second most read story on the BBC server. The number one story is about the new micro-holographic optical disc that is visually similar to ordinary DVDs but it can store up to 500 GB of data. Click the image for the story.

Herbert Kroemer & innovation

A 78-minute 2005 UCSB lecture by Herbert Kroemer, the German American 2000 Nobel prize winner in physics (for semiconductor heterostructures), has been recommended by his proud disciple ;-), namely Gene.



Aside from some cute details about the history of transistors, CDs, LCD, LEDs, and the evolving appraisal of the importance of related phenomena, he said lots of important general things that I fully subscribe to, for example

• the key applications of a discovery create completely new things and possibilities, so it is wrong to judge new discoveries according to their ability to solve the old problems only and to supersede existing gadgets
• in other words, more generally, in the most valuable research (and the most valuable parts of the learning process), the results (and applications) are not known to start with
• the methodology allowing one to learn the necessary stuff and independently solve problems is more important than individual pieces of knowledge
• the key physical ideas and methods are usually contained in a simplified model which should therefore be naturally understood first, instead of attempting to solve the most general problem at the very beginning
• it is completely sane that the business world tries to pay for research influencing a finite future and the business world shouldn't be attacked for behaving rationally
• however, the researchers must still be given the freedom to investigate questions that are important according to the pure scientific criteria of the research itself
• an expert cannot care much about the fame of other people who offer their opinions on some research, its value, and the answers - he must be able to judge these opinions according to their content.

Insightful D-branes

I believe that the best hep-th paper today is the last one,

Insightful D-branes (PDF)

by Gary Horowitz, Albion Lawrence, and Eva Silverstein. The authors decided to say something new about the fate of information near the black hole horizons.

In order to do so, they had to find an appropriate model of a black hole with many descriptions. So they picked an orbifold of AdS5 x S5 with the orbifold group identifying points at some hyperbolic purely space-like slice of the past light cone of a point in AdS5 x S5.

Much like for the four-dimensional Schwarzschild and other black holes, one can use Schwarzschild-like coordinates that don't see inside the horizon; these coordinates are often natural in unitary descriptions where quantum mechanics is respected. And one can also use other coordinates that do see beneath the horizon; such descriptions take classical general relativity seriously. Many of the black hole paradoxes can be reduced to the mysterious relationship between these two types of a description.

Because they want to study how physics changes at different radial distances from the singularity, they use spherical D3-brane probes - the same kind of spherical D3-brane shells whose collapse could have created the black hole in the first place. In the dual AdS/CFT description, their position is given by the six adjoint scalars.

They investigate the dynamics of these scalars i.e. these D3-branes. In some approximation, they're governed by DBI-like actions. And the eigenvalues of these positions themselves are primarily affected by the inverted harmonic oscillator potential. For different energies, starting from the very low energies that are well below zero (well below the maximum of the potential), this degree of freedom can either

• (A) classically bounce; the bulk sees D3-branes that never reach any horizons; they also think that naked singularities are removed by some repulson-like dynamics
• (B) bounce with large quantum corrections; the bulk image includes time-like singularities cloaked by outer and (unstable) inner horizons
• (C) reach the origin of the configuration space; the bulk theory interprets it as the space-like singularity

This is a nice and simple map that links qualitatively different causal diagrams with different types of motion in the system that is as easy as the inverted harmonic oscillator. Great. That's the kind of a true insight that is important in physics: a classification of difficult things is correlated with a classification of simpler things.

The pictures where the horizon is crossed or not crossed are related by time-dependent field redefinitions for the Yang-Mills scalars. These words may sound satisfactory to someone but I simply don't see how these words actually solve any of the problems. There are still two possible pictures: in one of them, the probe never gets inside; in the other picture, it does.

These two pictures differ by the amount of information that can live in space. According to black hole complementarity, the information about the black hole interior should not be independent. It seems that the authors think that they have confirmed this principle but the details how this occurs are not clear to me.

After all, a field redefinition is a trivial operation. But on both sides, one should have some consistent rules about the boundary conditions, normalization conditions, and domains where the scalars (and time) are allowed to take their values. Most importantly, how many "places" on the D3-branes (where excitations can live) are there?

The two pictures, with the black hole interior and without the black hole interior, seem to have different answers to all these questions. And so far I don't see how the different answers are being reconciled by the paper. They say that in the Schwarzschild coordinates, the infalling D-branes are slowing down and the corresponding adjoint scalar fields become heavily fluctuating.

Well, it is almost certainly the case. But if they believe that they have a well-defined, essentially integrable system to analyze the situation, shouldn't it be possible to say some details about this transition? How do these large quantum fluctuations look like and how do they imply - via the field redefinition - the mostly "empty space" seen by the infalling observer and/or the nearly thermal radiation leaving the black hole? How is the information about the black hole interior (and the black hole entropy) really stored in these highly fluctuating degrees of freedom?

My feeling of confusion is not being helped by Figure 4, either. They reproduce the topologically trivial "Penrose diagram" of a black hole by Ashtekar and Bojowald, featuring a blob called "nongeometric region" but no horizon. The moral purpose of this picture is to say that in quantum gravity, there are no strict causality rules. Indeed, that must be the case because the information can get out. So all "black hole interiors" are just artifacts of the classical approximation and don't exist at the quantum level.

That's almost surely the case. But is there something more about the picture that should be taken seriously? What does it mean to draw a geometric picture (namely a Penrose diagram) of a nongeometric region? Isn't it obviously impossible? Where is the boundary of the nongeometric region? Is it near the singularity, near the horizon, or is the whole spacetime slightly nongeometric - with the "effect" and "degree of nongeometricity" decreasing as we are going away from the singularity? If these questions can't be answered, I think it is misleading to draw any new Penrose diagrams. Penrose diagrams are meant to tell us something the classical causal structure of a geometry. If the latter doesn't exist, Penrose diagrams shouldn't exist, either.

Although the situation was probably nicely chosen to allow them to do a relatively complete analysis, I don't feel that this analysis has been quite made so far. The term "field redefinition" seems to be a vacuous buzzword. As a physical operation, it seems to lack the beef (although it may look complicated if the Yang-Mills symmetry is being gauge-fixed differently on both sides) and it seems that the basic questions - e.g. whether the degrees of freedom inside and outside in some slices (that see inside) exist independently at the same moment - have not yet been answered here.

There is one more way to explain why I feel that the gap hasn't quite been removed. There are essentially two basic descriptions. One of them is that of classical GR; it includes the black hole interior as an independent piece of space; nothing special happens near the horizon; the information gets lost. The other naturally talks about the black hole exterior only; it is manifestly unitary and quantum-mechanics-friendly; but it doesn't see anything beneath the horizon.

The basic gap is in between these two descriptions. It is clear that the classical GR description is only correct in the classical limit; while the second, pure quantum description a priori fails to imply the correct limit with the empty and seemingly independent black hole interior. From a solution to those black hole puzzles, I expect the authors to have a picture that satisfies the quantum principles - including unitarity and complementarity; but also can be used to derive all the features of the classical physics of GR; and tell us something beyond that, too.

That's why I am probably going to continue to think about these matters because they have not been fully resolved by these toy models.

Birth of oil: geology, temperature, CO2

The left-wing blogosphere tries to humiliate Rep Barton and climate change at geological timescales. I am stunned by the extremely low quality of the discussion at most blogs. They essentially try to picture Rep Barton as a Young Earth creationist - there is no justification for such a description here - and they ignore his question completely.

Dr Chu failed to give a particularly quantitative answer to Rep Barton; see Steve McIntyre's article dedicated to the same observation.

So let us ask again: Why is there oil in Alaska? Where did all the biological material come from? It turns out that continental drift was comparably important for the elevated temperatures needed to create oil as the global mean temperature. In this sense, Chu and Barton were comparably close to the truth, despite the emotional indications of many superficial blogs.



Late Jurassic, about 150 million years ago, when the world's largest oil fields were born. The continental drift has substantially changed the arrangement of continents since that time.

Here are the periods of the Phanerozoic eon, together with the fashionable life forms, temperatures, CO2 concentrations, and places where petroleum or coal was being born. Recall that the current global mean temperature is about 14 °C and the CO2 concentration, including the human contributions as of 2009, equals 385 ppm. You will see that the temperature used to be noticably higher and the CO2 concentrations used to be substantially higher. All the data are taken from Wikipedia.

The timestamps are written in between the periods:

• 542 million years ago
  Proterozoic era ends, Paleozoic era begins
• The Cambrian: 4500 ppm, 21 °C
  expansion of life, trilobites (anthropods)
• 488 million years ago
• The Ordovician: 4200 ppm, 16 °C
  marine animals, mollusca
• 444 million years ago
• The Silurian: 4500 ppm, 17 °C
  corals, mosses
• 416 million years ago
• The Devonian: 2200 ppm, 20 °C
  seeds, forests, many sharks, fish
• 359 million years ago
• The Carboniferous: 800 ppm, 14 °C
  sea stars, sponges, corals, fish, equisetales, insect, tetrapods, fungi
• 299 million years ago
• The Permian: 900 ppm, 16 °C
  invertebrates, reptiles, cockroaches, cynodonts
  Coal in Siberia, East Asia, Australia; Oil in the U.S.
  
• 251 million years ago (extinction event)
  Paleozoic era ends, Mezozoic era begins
• The Triassic: 1750 ppm, 17 °C
  no coal, new corals, ammonites, turtles
• 199 million years ago
• The Jurassic: 1950 ppm, 16.5 °C
  dinosaurs, crocodiles, conifers, coralline algae
  Oil in Middle East, North Sea, Siberia (part)
• 145 million years ago
• The Cretaceous: 1700 ppm, 18 °C
  figs, magnolias, some mammals, birds, modern sharks
  Oil around Venezuela; Earth by 4 °C warmer than today; see Climate Audit
• 65 million years ago (extinction event)
  Mesozoic era ends, Cenozoic era begins
• The Paleogene: 500 ppm, 18 °C
  birds and mammals explode
• 23 million years ago
• The Neogene and The Quaternary Period (last 2 megayears): 280 ppm, 14 °C
  mammals include early humans
• Today
• Our world in 2009: 385 ppm, 14 °C

You can see that there have been several periods, e.g. The Ordovician, when the CO2 concentration was more than 10 times higher than it is today. But the temperature only differed by 2 degrees Celsius. And this is true despite the fact that the bulk of the CO2-temperature relationship is actually caused by outgassing rather than the greenhouse effect.

At any rate, both global changes as well as the continental drift have been contributing to the ability of different regions to create petroleum while the CO2 has been violently changing and has been irrelevant for the climate throughout the history of the Earth.

And that's the memo.

Bonus: geological climate sensitivity

Finally, let me perform a simple exercise with Mathematica: by the way, the price is now GBP 195 plus VAT only. Click the logo below.

While I have emphasized that the CO2-temperature relationship is mostly caused by the influence of temperature on the gas concentrations (as seen through the 800-year lag in the Vostok data), let us assume that this whole relationship is caused by the greenhouse effect. And let us calculate the climate sensitivity - warming per CO2 doubling - from the 11 geological data points above.

Download the geological notebook

Let us define the CO2 concentration and temperature vectors:

ppm = {4500, 4200, 4500, 2200, 800, 900, 1750, 1950, 1700, 500, 280};
temp = {21, 16, 17, 20, 14, 16, 17, 16.5, 18, 18, 14};

Now, calculate the base-two logarithms of the CO2 concentrations:

logPPM = N[Log[ppm/280]/Log[2]] =
= {4.0064263, 3.9068906, 4.0064263, 2.9740048, 1.5145732, 1.6844982, 2.6438562, 2.7999754, 2.602036, 0.83650127, 0.}

Finally, we will find the linear fit for those data:

data = Transpose[{logPPM, temp}]
lm = LinearModelFit[data, logCONC, logCONC]; Normal[lm]

Now, get ready for a shock. The result is

14.854913 + 0.89326377 logCONC

This means that for 280 ppm, the predicted temperature should be 14.85 °C, higher than today. For 385 ppm, this function predicts 15.26 °C. The warming expected from a CO2 doubling, based on those 11 ancient historical points, is just 0.89 °C. Now, this result assumed that the whole relationship is due to the greenhouse effect. Actually, less then 10% is caused by the greenhouse effect.

This correction would imply that a sensible estimate for the climate sensitivity would be just a tenth of a degree, much less than Richard Lindzen's minimalistic estimates.

Of course, many other changes have occurred on the Earth. At any rate, geology strongly indicates that the CO2 concentration has always been irrelevant and it is sensible to expect that it will be irrelevant in the future, too. The sensitivity - warming caused by the CO2 doubling - is between 0.1 °C and 1 °C.

The Droste Effect

Click the image for a whole article at the Wolfram blog, with many additional conformal transformations of this picture.

The Droste Effect (the term comes from Dutch) involves images within larger images that are similar to the original ones. However, conformal mapping may be used to generate more fascinating images. For example, can you tell which girl on the picture is real and which girl is a level-n image? Well, "n" is continuous in this case. See also a movie. ;-)

It's too late now but it could be fun to play with similar algorithms a little bit later.

By the way, Wolfram Alpha will be presented on Tuesday 3:00 pm at the Harvard Law School.

A story of a Chrome bug

Finally, a computer event unrelated to Stephen Wolfram. For quite some time, I was pushing the creators of Google Chrome to fix a bug: in blogger.com, one couldn't expand the "mini-previews" of postings (or slow comments) in the list, by clicking a triangle or the nearby title: see the screenshot. This bug, being the most frequent reason for me to run Firefox or MSIE, became the issue 8536.

Fifteen minutes ago, it was fixed. It was enough for them to modify the default answers to some XML requests from Undefined to Null - but the details how they found it and where they found it clearly look more technical than what your humble correspondent could comprehend.

Polish NAS joined climate skeptics

It took us two months to learn that the Committee for Geological Sciences of the Polish National Academy of Sciences has joined the climate realists. In their February 2009 statement,

Translation published by Benny Peiser
Original Polish statement (PDF)

they enumerate dozens of examples of natural processes that have been changing the climate from the birth of our planet, at all time scales, locally and globally.

It explains why the recent changes were small in comparison with the historical evolution and why the most recent measurements do not offer us enough data to validate complex models. The scholars agree that the greenhouse effect is real and identify water vapor as the key greenhouse gas. They emphasize that the climate must be studied in its entirety, including the geological context, and the focus must shift away from CO2.

The academy diplomatically concludes that adaptation to whatever occurs is the way to go and that taking dramatic and expensive steps to reduce just some selected greenhouse gases which are just a small portion of the drivers of the climate may turn out to be counterproductive.

Let me say that I am convinced that pretty much all natural and exact scientists in Central Europe would subscribe to this statement but I am not sure whether this fact is enough to eliminate the hordes of "alternative" physicists, to put it extremely mildly, who have flooded many Western and other academies, schools, companies, and journals during the most recent 5 years or so.

By the way, when we talk about Poland, the country is preparing to ban T-shirts with commie mass killer Che Guevara. Meanwhile, David Duke is visiting Czechia, planning to support a Czech Nazi group and apparently believing that it is legal in the Czech Republic to be a former Ku Klux Klan boss. It is actually not quite legal to promote "movements attempting to suppress human rights" so he was arrested in Prague. Nazis, feminists, and similar crap, beware.

Hat tip: Benny Peiser and Roger Helmer, a Tory MEP



Bonus: Prague skyscrapers

By the way, Prague mayor Dr Pavel Bém, the guy who has been to Mt Everest, has won the first award for his vigorous support of the plans to build skyscrapers in Pankrác, a Southern suburb in central Prague. Prague deserves at least a modest skyline.

The golden city displays all the architecture styles of the past and the 21st century skyscrapers shouldn't be missing! What would the 23rd century tourists think about such a historical hole? ;-)

The award is Petroleus Mostensis 2009 (Ropák 2009) and it has been decided by the nation's green bigots organized in the "Children of the Earth" (Děti Země) movement. But I am sure that Dr Pavel Bém is going to be proud, anyway. The bigots have also appreciated Bém's support for speedy highways in Prague.

Dark gulping: dark matter black holes

Anthony Watts wrote about the fraudsters associated with the Catlin Arctic Survey who are selling catastrophic measurements by Pen Hadow et al. before these measurements are actually measured. ;-)



GRS 1915+105 is almost certainly stellar in origin, despite its being the largest stellar black hole in the Milky Way that we know: there is also another star orbiting it, too.

But I have also noticed the screenshot of a Yahoo page where the problematic ad appeared. It is about dark gulping.

See Google News, Yahoo/Space.com, Softpedia, MSNBC,

claiming that superlarge black hole holes - with billions of solar masses (such as those found at large galactic centers) were created by a collapse of dark matter.

It seems obvious to me that such things can take place. Gravity only takes about the total mass and momentum, not the "color" of the matter; the only question is how often these collapses occur.

There is more mass stored in dark matter than baryonic matter. On the other hand, dark matter tends to be more diluted. I am not sure which difference wins - and it is better for me at this moment to trust the simulations of others. But at the end, the number of collapsed-dark-matter black holes could be comparable to the black holes of baryonic origin: but they will be substantially larger.

When they're already created, you can't tell them apart. Recall that black holes have no hair.

Victor Stenger: Quantum Gods

Amanda Gefter reviews Victor Stenger's new book in Nude Socialist. The book, "Quantum Gods" (click to buy), looks at several religious directions that are mostly based on the following two memes about quantum mechanics:

1. Because of the uncertainty principle, there is a lot of room for God to control the world, without contradicting the laws of physics.
2. The mind and the Universe are linked via quantum mechanics.

Gefter's article indicates that he correctly - from a physics viewpoint - says that the first verse is incorrect because the quantum outcomes have to be truly random, unaffected by any data from the past light cone (and probably not even by God's master plan, although this no-go theorem may be harder to prove than the free-will theorem haha).

The second religious principle is incorrect because quantum mechanics applies equally to all systems in the world, "conscious" and "unconscious" ones (these two physically differ by their ability to manipulate with the information only!), and the only relevant difference that separates "objects following the quantum logic" and "objects within the realm of classical intuition" is based on the speed of decoherence.

The book correctly says - in my opinion - that the main message of EPR-like phenomena is that one has to give up determinism and realism, not "locality" (even claiming that most physicists agree with it - a statement that I am sometimes uncertain about), and it offers counter-arguments against the Bohmian school, too.

Stenger also promotes decoherence as an important principle.

Max Tegmark is promoted to a neuroscientist - his order-of-magnitude estimate is used to argue that the brain essentially works as a classical (biological) computer, and can't be viewed as a coherent quantum (biological) computer: decoherence is at least 10 billion times faster (or affecting much shorter distance scales) than what would be needed for quantum mechanics to be relevant for our thinking.

A funny aspect of the article (and the book?) is this picture of Maharishi Mahesh Yogi. In the very early 1990s, after the Velvet Revolution, his Indian-looking disciples came to our high school in Pilsen, attempting to make us meditate.

Although these particular people seemed completely unable to answer any of my deeper physics questions, :-) their chances were rather high in the case of your humble correspondent because their booklets explaining the unified field theory, strings, and their links to their religion were particularly impressive - to the extent that I began to ask whether they could have been right.

Later, I learned that ex-particle physicist John Hagelin - a genuinely powerful brain - was behind this unexpectedly strong impression that the booklet had on me. In his previous incarnation, Hagelin wrote famous articles about the search for violations of quantum mechanics; weak symmetry breaking in SUGRA; GUT models; FCNCs; search for SUSY at a p-p collider (just like the LHC: it was written in 1983!), and many other things. A damn serious scientist.

Later, he has developed the whole advanced-physics infrastructure for the Maharishi church (and his The Natural Law Party of the USA, for which he has run for POTUS a few times) so that it was based on many details that were more scientifically solid and detailed than the scientific bases of many "atheist" institutions. ;-)

If you allow me to be more specific, you should look e.g. at The Discovery of the Unified Field, a material written by the Maharishi Global Administration in 1999. If Nude Socialist began to print such stuff, their treatment of theoretical physics would dramatically improve, even though this particular article about Stenger's book might be a hint of a more optimistic development. ;-)

Hat tip: Tereza N. ;-)

Waiting for N heads in a row

David Berenstein offered us the following:

Problem

You toss a coin and you win if you get N heads in a row. What is the average number of throws for a win?

General answer

The average number of throws is actually

2^N+1 - 2.

For example, for N=3 heads in a row, you need 16-2=14 throws while for N=5 heads in a row, you need 64-2=62 throws to get five heads in a row. The numbers 2, 6, 14, 30, 62, and maybe 126 also appear as dimensions in the Kervaire invariant problem in mathematics.

A somewhat elegant derivation (LM)

Imagine that you throw the coin L times where L goes to infinity.

Any sequence of N consecutive throws clearly has the probability of "1/2^N" of being "N heads in a row". For a fixed and large "L", let's count the number of throws "M" that are the last throws completing a short sequence of "N heads in a row". Clearly, there are "L times the probability" i.e. "M = L/2^N" of such throws for a very large "L". All the throws are always independent from each other.

The average number of throws per one event of "N heads in a row" equals the opposite ratio "L/M", namely the number of throws, "L", divided by the number of the "N heads in a row" events, "M = L/2^N". The ratio would be "2^N", i.e. the inverted probability.

However, we shouldn't count the overlapping events.

We only allow a new sequence of "N heads in a row" if it appears at least "N" throws after the previous one. In the first approximation, this means that exactly 1/2 of the "N heads in a row" events have to be erased. They're the events (their last throws) that actually complete "N+1 heads in a row". All overlapping pairs of "N heads in a row" events have to include "N+1 heads in a row", so we have erased all the overlapping events.

In this approximation, we have

M = 2^-N L - 2^-N-1 L... = 2^-N-1 L...

"N heads in a row" events. Let's go to higher orders. Why?

We have actually subtracted too much from "M". It is allowed to have "N+1 heads in a row" but only a small fraction of these events have to be double-counted. How many? Well, "2^{-N}" of them. That's because if one sequence of "N heads in a row" is immediately followed by another sequence of "N heads in a row", you should count the sequence of "2N heads in a row" twice.

However, once again, one is only allowed to add those events with "2N heads in a row" if they are followed by a tail, so one half of them:

M = 2^-NL - 2^-N-1L +
+ 2^-2NL - 2^-2N-1L +...

It's clear where we're going. The sequences of "2N heads in a row" have been properly counted as two events, but sequences of "3N heads in a row" should actually be counted as three events, assuming that the 3N+1-st throw is a tail, so we must refine "M" as

M = 2^-N L - 2^-N-1 L +
+ 2^-2N L - 2^-2N-1 L +
+ 2^-3N L - 2^-3N-1 L +...

Finally, the whole procedure is well-defined and convergent. "M" can be calculated by the following geometric series

M/L = 2^-N-1 + 2^-2N-1 + 2^-3N-1 +...

which is easily summed up to see that

L/M = 2^N+1 - 2

which is the required average number of throws per a completed, nonoverlapping sequence of "N heads in a row".

Appraisal

Isn't it much more transparent and intuitive than any of the derivations on that page or elsewhere on the Internet? ;-) That's the power of perturbative expansions.

Not the end of the story

In the fast comments, you will find a much simpler, recursive calculation of the expectation value of "L/M" as a function of "N" by "mathematician".

Earth Day

Our Earth has her day today. Congratulations. I wish her to get rid of the green shackles soon.

If that happens, we won't have to travel 20 light years to find another planet where life is legal. ;-)

You may help her to get liberated, too. Shoot your environmentalist today!

After 45 days, there is a new official sun spot displayed on the surface of our star. The spotless streak has been amazingly long, anyway.

Pen Hadow et al. are making almost no progress in their planned journey to the North Pole. The global sea ice area remains substantially above the average for April 22nd.

The transition to ENSO-neutral conditions is pretty much completed. While some circulation patterns reflect a weak La Nina, the Nino 1+2 region indicates a substantially positive El Nino anomaly +0.8 °C; the remaining regions are essentially at zero.

Michael Atiyah: 80th birthday

Sir Michael Atiyah, one of the most influential 20th century mathematicians, is celebrating his 80th birthday tomorrow. Congratulations!

See The Herald to learn about the Atiyah Fest...

Although he has been a mathematician, his results - especially those in algebraic topology - have become essential in modern theoretical physics in general and string theory in particular.

The most well-known result is the Atiyah-Singer String Index Theorem, proved in 1963. It is often called simply the "Atiyah-Singer Index Theorem" although this short name doesn't quite reflect the depth of the result - i.e. its proximity to the most fundamental mathematical features of our string-theoretical Universe.

Sir Atiyah has also co-authored a famous paper with Ed Witten on M-theory on manifolds of G_2 holonomy, one of the cute 100-page papers that I couldn't have resisted to read, and a related, shorter, and comparably famous paper with Maldacena and Vafa about the M-theoretical counterpart of Calabi-Yau flop transitions.

His work on K-theory turned out to be important in the physics of D-branes. The ADHM construction, of which he is the alphabetically first co-author, was able to understand how D0-branes dissolve within D4-branes and how to describe the space of instanton solutions in an alternative way - long before this trick was needed or understood by the physicists. Consequently, many of his findings may be viewed as prophesies that became physics long after Atiyah saw their importance.

The index theorem and string theory

Because a lot of misinformation and vitriolic denial is being promoted by the stinky sweepings of the blogosphere that a rapidly dwindling (see top 3 string theory blogs) but unfortunately still nonzero number of people keeps on reading, let me recall why the Atiyah-Singer String Index Theorem is so closely linked to string theory.

In general, the theorem allows us to calculate certain analytic data - the indices i.e. sums and differences of the numbers of independent solutions to differential equations of various kinds - in terms of topological data about the base manifold, e.g. the Betti numbers or the number of holes in the manifolds.

This topological interpretation and derivation of analytical or physical data (or the opposite procedure) is one of the main points of perturbative string theory (and, arguably, not only in the perturbative one). Also, string-theoretical applications of the theorem form a dense subset of the space of all applications of this theorem. As all theorems in mathematics, it is more general than its main physics application. But in some sense, the overlap is so substantial that it makes sense to identify the theorem with its explanation and interpretation within string theory.

The most important special example of the theorem is the classic Riemann-Roch theorem. If you open Green-Schwarz-Witten's textbook on Superstring Theory, volume 1, page 162, you will see that on a real two-dimensional Riemann surface, the number of independent moduli B_g and the dimension of the group of conformal isomorphisms C_g (both of which can be written as the number of zero modes for various tensors, namely the conformal ghosts and antighosts, as can be easily seen) satisfy

Delta_g = C_g - B_g = 3(1-g).

The right hand side is proportional to the Euler character (it's equal to 3/2 times chi) which can be calculated from the integral of scalar curvature. This result is crucial for the consistency and non-vanishing-ness of loop diagrams in perturbative string theory - and its validity may be naturally proven by string-theoretical methods, too.

In volume 2, page 372, of the same GSW textbook, you find out that the index of the Dirac operator in 4k+2 dimensions can be calculated from the theorem, too. It's no coincidence that the second simplest example after "k=0" deals with "k=1", i.e. with six-dimensional manifolds. While the "k=0" case was essential for the string world sheet, the index of the "k=1" i.e. "d=6" Dirac operator is important because it determines the number of generations of leptons and quarks in the conventional compactifications with 6 internal dimensions (6+4 = 10). They are given in terms of the Euler character - or its generalizations in the presence of additional stringy physics.

Other generalizations involve signature indices and/or separate holomorphic/antiholomorphic exterior derivatives. A lot of work extending results of Atiyah and others has been done by Witten. They can be embedded into string theory. In many cases, the truncation to topological string theory is enough to see the whole structure.

Mathematics as prophecy in physics

Once the true physical meaning of these mathematical results - whose depth was always manifest to the big thinkers - is appreciated, one can use the other knowledge of the physical application (string theory) to search for the natural guesses how to generalize the results and estimate their importance. The interactions between mathematics and physics are very subtle, however.

So mathematicians often find generalizations whose physical meaning seems obscure or non-existent at the moment of the mathematicians' brainstorm.

However, if the mathematicians are deep, it often happens that the result is viewed as an extremely physical one a few decades later. It was surely also the case of the Atiyah-Singer String Index Theorem that appeared in front of their eyes five years before string theory was officially born in physics - and almost 20 years before the relevant mathematical methods became common in physics calculations (especially the modern BRST quantization of string theory; and derivations of low-energy physics of string theory).

Mathematicians are often ahead of their time. But those 20 years are close to the upper limit at which the mathematician can still feel genuinely happy about her or mostly his work. If he or she is a century ahead of the physical world, I am afraid that he or she may remain misunderstood.

Congratulations to Sir Atiyah once again.

Marbles (Kuličky): a film

Pilsen is just hosting the 22nd Festival of Czech films. The Czech movie Marbles (Kuličky) became another part of my week in the cinemas - and it was extremely good.

See the trailer (Czech)

Warning: spoilers are included below

Its director, Ms Olga Dabrowská, has connected four stories by one unifying theme: the natural ability of women to manipulate with men. The first story takes place among children who play on the playground; the actors in the last story are above 80 and the exploitation of the man by his wife doesn't even end with his death.

The first story, The Wedding, is very short. Children play a "wedding game". As soon as a boy becomes a "husband", he is prevented by his new "wife" from joining others who search for a treasure.

We get to the world of teenagers (around 14) in the second story, Mom's Little Angel. We meet a girl who controls a boy whom she likes by telling him that she has cancer. However, the main hero of the story - and another example of subtle blackmailing - is another girl (Tereza Nvotová) who hates her mother's new intimate relationship with a man. The daughter decides to have sex with him, too. By bringing him into this impossibly painful situation, she probably manages to terminate his relationship with her mother.

The third story, A Moral Imperative, is about adults. An ugly Christian woman who lives in a stable family background brings her attractive and adventurous blonde classmate from the high school to a Christian weekend in the countryside. The blonde's own main goal is to pick a man and she finds the Catholic priest himself (Jiří Vyorálek) to be the most eligible one. At the end, she makes him break the celibate by an interaction that both people find satisfactory - an event that is uncovered by the other believers.

The blonde is clearly not presented as the ultimate "evil": many of the Christians are shown to be driven by jealousy and the desire to screw other people's feelings. The church hierarchy is ready to forgive the priest's sins but he realizes the moral responsibility and leaves the church for the woman who has given him a gift: her positive pregnancy test.

The final, fourth story, Slowly I Am Fading Away, is about a very old couple. He is a poet. She cooks and washes for him, and so on, but you can see how much she enjoys to restrict his freedom and especially his love for poetry - and how much she loves to paint herself as the important person. The guy passes away: she has arguably contributed to his decline. Her comments above his grave are strikingly similar to those above the bed when he was still alive. At least, a rock band uses his lyrics, Slowly I Am Fading Away, in their new vigorous song.

Recommended (although I am afraid that non-Czech readers might find it difficult to see it).

44th Academia Film Olomouc 2009

If this trailer has just automatically appeared, that's because it was pre-programmed and I am probably on my way to Olomouc, the spiritual center of Moravia, to supplement one of the TV programs - that you probably know very well, that you may see in the trailer above, and that is going to be aired on AFO 2009 - with a spoken (and PowerPoint) presentation. ;-)

If you think that some of the programs are not quite new, it's because not every annual festival in Olomouc is devoted to fundamental physics.

Sorry for the absence...

Sunday update

I can't review everything that has taken place - because it was a lot of stuff. By the way, Olomouc is a beautiful historical city with lots of churches and an anomalously low number of tourists. I took about 200 pictures, too.

There have been documentaries such as Most of the Universe is Missing (BBC) which was followed by a talk by Prof Kulhánek about dark (and visible) matter and dark energy, and The Elegant Universe (PBS) that was followed by my talk on similar topics.

All the movies were introduced by the official intro, explaining that crop circles can't be caused by the U.F.O. (and showing the U.F.O.'s along the way), and usually also by a short movie shot from the reference frame of a monkey (or at least a student of a film academy pretending to be a monkey).

The following private discussion with many participants was mostly dominated by an ingenious woman who was inspired by my talk to realize that the sound results from the world sheet of strings, using modern language. She couldn't believe anyone that the sound could have had anything to do with the air.

Other discussions about the infinite hierarchization of matter (vs the Planck scale) and lots of other topics came after my talk.

On Saturday night, I saw Jesus Is Normal (Take It Jeasy, in English), a documentary about a Christian sect that is very similar to one that I became familiar with 12 years ago (through an ex-GF of mine).

I was impressed by the movie - and by the sensible answers of the film director, 20-year-old Ms Tereza Nvotová (greetings!) in the question period. Let me keep other things linked to TN private. ;-)

There have been many stories linked to the trip. For example, in the train, when I was returning to Pilsen a few hours ago, a freshman next to me studied mechanics of the continuum and he or she was confused why one coefficient of thermal expansion was three times another one. After observing one minute of his or her suffering, I couldn't resist and explained him or her that one of them referred to the linear expansion while the other was about the expansion of the volume etc. He or she was excited how much sense it made. Someone is lucky. ;-)

TBBT: Czech dubbing

Check 1x01 Pilot and 1x02 Hypotéza otrubové vlákniny to compare the Prima Cool dubbing of "Teorie velkého třesku" with the original.

I think that the translation and synchronization are OK (and the translation is sometimes creative) but the style of the Czech characters looks weak to me.

For example, Sheldon's voice is too ordinary and the Czech actor simply doesn't seem to be a high-IQ person at all. This is amplified by his frequent colloquial Czech: a huge problem. The Czech director seems to have lost the whole point here (and maybe they simply haven't found a good Parsons counterpart). Czech Leonard's voice is too self-confident (very different from Leonard's frustrated discourse) - and indistinguishable from Sheldon, anyway. The Czech creators seem to have misunderstood all the specific features of the individual characters.

Well, I don't like Czech Penny's voice too much, either. It sounds just like all the other dubbed sitcoms. Rajesh has no Indian accent and sounds insufficiently shy. And Wolowitz is bad at basic things like imitating Hawking's computer voice.

There are some errors in the translation, too. For example, Penny talks about her work about a girl who moves from Lincoln - but she is from Omaha so it's not about her, she says. Lincoln is translated as "Nebraska" (because no one knows "Lincoln" the city here) which completely screws the joke because Omaha is in Nebraska, too. It doesn't sound manifest that Penny is more ordinary than the boys.

Well, let me stick with the English original.

Claude Allègre may become French minister

La Depeche (autom. translation to English)

The name of Claude Jean Allègre is returning regularly in the discussions about the new minister of environment in the reshuffled French government led by Fillon. He would become either the minister of the environment or the minister for research.

See also Google News (French). By the way, if your browser doesn't have a button to instantly translate foreign web pages to English, drag-and-move this blue "English" button among your bookmarks (preferably in the toolbar).

These rumors are fascinating because Claude Allègre, an achieved geochemist, is an outspoken newborn global warming skeptic: see Lawrence Solomon's story and Allègre's article, The Snows of Kilimanjaro.

Via Marc Morano's Climate Depot, the website of the new superpower that will defeat climate alarmism on this planet ;-)

Catlin Ice Survey shows that global warming predictions were wrong

Pen Hadow et al. went to the Arctic to measure ice. Most of their scientific gadgets froze and broke down - but they're still doing manual drilling.

One of the predictions by the people who believe that there is a global warming worth talking about that the explorers were expected to confirm was the proposition, widely published in the media, there would be no first-year ice on the place of their current location (relatively close to the North Pole) in the middle of April 2009. That's roughly because such ice would have been created last Fall which was "warm" in the Arctic and ice can't be created in such conditions, those people's (sloppy) reasoning goes. So Pen Hadow et al. "didn't expect first-year ice".

In reality, they found something else: there is first-year ice, after all. The scaremongers also think that thick ice can't be created within a few months, so various melting changes are permanent.

Well, this new ice is actually 1.77 meters thick in average which is, technically, very thick first-year ice. You may remember lots of articles being released almost every day during the last half a year or so that despite the sea ice area's being above the normal, the "volume" is surely smaller because the ice area is composed out of first-year ice which "must" be thin: see, for example, Ocean Conserve from April 6th, 2009 (also in The Guardian). Believe Hadow or not, it's not thin and all the newspaper articles were bunk.

In other words, ice comes and goes all the time - lots of it and very quickly - get used to it, chaps with as overheated brains as Sprite is frozen. The main threat for Pen Hadow et al. is no longer the harsh weather (or antiseptic creams pretending to be toothpastes) but the possible decision of their orthodox base that by releasing the inconvenient truths from the Arctic, the explorers have become heretics who no longer deserve an airplane. ;-)

Via Anthony Watts.

Strings link the ultracold with the superhot

An award-winning science writer and the editor-in-chief of Science News, Tom Siegfried, wrote a nice popular article about the string-theoretical dual of various strongly coupled systems.

When experimenters studied the quark-gluon plasma, a large chunk of excited nuclear matter (of colliding golden nuclei), they thought it would have to behave as a gas or plasma: the temperature was so high and the stuff was so hot! Instead, what they saw was that the material actually behaved as a liquid - a seemingly cold type of matter.



And it wasn't an ordinary liquid: it was actually a liquid with a very low viscosity. In fact, it had the lowest viscosity that a liquid of the same entropy density could have: a perfect liquid! Despite a trillion of degrees Celsius, it behaved like a pretty cold liquid. Meanwhile, the string theorists already knew why this thing would be observed.

Surprisingly, an ultracold "gas" - Lithium-6 that was cooled just to dozens of nanokelvins in 2002, which is a temperature 19 orders of magnitude cooler than the previous, nuclear stuff, behaved in the very same way. A perfect liquid, too.

The minimum ratio of viscosity and the entropy density can be translated in another way: it is actually the maximum ratio of the entropy density to viscosity. For a fixed viscosity (and volume), which physical system has the highest entropy density (and therefore the net entropy)? Well, in the gravitational context we know the answer. Black holes maximize the entropy. They're the ultimate bound state of matter into which the matter collapses into, and by the second law of thermodynamics, they must maximize the entropy among all such bound systems.

It turns out that string theory guarantees that these fully thermalized systems necessarily try to maximize the entropy-to-viscosity ratio. It's because these systems have an equivalent, i.e. dual description on the boundary of an auxilliary AdS space with one additional dimension: the dual description of this matter is nothing else than black holes. It has to be because it is a theory of quantum gravity where black holes inevitably arise under mild assumptions.

The picture correctly describes not only all the surprising qualitative properties of this type of matter - including the ability of the plasma to "catch" even heavy quarks - but also many quantitative features - such as the viscosity-to-entropy_density ratio itself. These experiments prove that the gravitational force is unified with other types of forces and matter in ways that people couldn't have even imagined - and in ways that can only be explained by string theory.

It used to be thought that the gap between the typical energy where quantum gravity takes over - the huge Planck energy - and the characteristic energy scales of other types of forces will remain huge forever. Even reasonable people thought that it would mean that no conceivable unification could ever have observable consequences.

However, the observation of the strongly-coupled systems above show a very different picture. Those systems are equivalent to a warped geometry where a stringy theory of quantum gravity lives. Because the length scales (and, inversely, energy scales) in the ordinary four-dimensional spacetime depend on the position in the fifth dimension (according to the warp factor), the overall scaling of the distances in the 4D space kind of depends on the type of physics one considers. Each type of physical phenomena has its typical scale which gets translated to different positions in the fifth dimension.

The proper distances in the five-dimensional bulk can therefore differ by large factors from the distances as seen by the projection to our four-dimensional spacetime. Well, all these things mean that Newton's constant derived for the dual gravity of many of the systems above may be very different from our four-dimensional Newton's constant: but it can still describe the same gravity because this Newton's constant may be obtained from a higher-dimensional one by a different truncation.

This dual bulk AdS gravity is just one way how to connect those seemingly non-gravitational systems with physics of quantum gravity. Who could have thought that the unification of ordinary forces with gravity will force us to solve the strong coupling limit of mundane pieces of matter - such as the quark-gluon plasma or Lithium 6? However, string theory implies that many more links, dualities, and transitions exist between the gravitational force and other forces. All of them are true and all of them are pretty much inevitable as long as one believes the experiments above as well as straightforward mathematical derivations.

The basic strategy how to unify gravity with other forces used to seem "obvious" in the past. But Nature has prepared many surprises to us. Even extremely non-gravitational - and, indeed, mundane low-energy - forces and phenomena are equivalent to a quantum gravitational system in string theory. Some forces get unified with others if their backgrounds are non-trivial (e.g. curved); others do so if their coupling constant or the density of particles is very high (or strong).

AdS gravity gets unified with the forces governing the ultracold Lithium-6 in a tighter way than anyone has imagined as recently as 15 years ago: they're completely equivalent. The relevant space is asymptotically AdS, which controls the high-energy phenomena, while the geometric arrangement near the "center" of this space carries the same information as the detailed low-energy properties of the quark-gluon plasma or the Lithium-6 gas.

The existence of the normal, four-dimensional gravity implies that the new fifth coordinate has to be truncated, so that energy scales exceeding the ordinary four-dimensional Planck scale are eliminated. Such a truncation has to follow some consistency rules - including a "continuity" with the bulk physics - and these rules are determined by string theory. This point is meant to emphasize that the ordinary four-dimensional gravity is inevitably connected to the "auxiliary" gravity used to describe the "perfect liquid" systems.

As we have mentioned, besides this unification, there are other insights that unify the forces in other ways. For example, a graviton can be continuously transformed into a photon through the Kaluza-Klein mechanism (compactification). Such a photon may be geometrized as a deformation of a singularity, an excitation on a D-brane, and so on. The whole world is thus represented as a grand quantum generalization of Riemannian geometry we are familiar with from general relativity, something that Einstein always wanted. It is filled with lots of links between objects and concepts that were thought to be independent and different in the past.

Einstein couldn't have found the right picture that unifies all the forces and matter in this way because he dismissed quantum theory and all the majestic equivalences, dualities, and transitions discovered by string theory only work if quantum mechanics is taken completely seriously: they finely depend on it. But it is clear that if Einstein were ultimately able to accept that quantum mechanics was inevitable, he would have known that string theory has realized all his dreams and many more.

All these things are amazing and I simply cannot respect anyone as a theoretical physicist if he or she is alive and if he or she hasn't understood the inevitability of all these conclusions about unification of forces even in 2009, decades after string theory has become pretty much established. And indeed, when suggesting the lack of intellectual respect, I am not talking just about the anonymous brainwashed human waste hiding behind another piece of the same waste that gathers on various crackpot forums such as Peter Woit's forum.

Bird migration and warming: an example of media manipulation

Today, various news agencies such as

AP, Reuters, The Telegraph

informed about one of those typical papers showing the "catastrophes" caused by global warming.

Some guys in England tried to calculate new favorite trajectories for 17 migratory bird species in a hypothetical warmer world, as projected by the most extreme warming scenarios, between 2071 and 2100. The result was that some of the species won't be affected. Half of them will face longer flights - and a few of them by as much as 250 miles.

Well, even though the conclusions are modest - some species would move their homes while others would not - it is a very speculative piece of work.

First of all, it is unlikely that the assumed warming will ever occur. Second, it is unlikely that they exactly know what the birds would be doing in such a different world. The most obvious reasoning says that even if the world gets warmer, then the birds will gradually move both their summer homes and winter homes somewhere further to the North (or away from the equator) by approximately the same distance and the length of their flights therefore won't change much.

As far as annual mean temperature goes, 250 miles is a big distance, corresponding to whole degrees Celsius. One can't expect "man-made climate change" to change the differences between temperatures on two places by whole degrees because the predicted warming is essentially uniform.

My argument about the uniform shift of their homes to the North (or South) is OK as long as the birds don't cross the equator or the warmest circle on the Earth. But doing so is useless because the temperature on corresponding places on both hemispheres is equal so there's no temperature-induced reason for vacations on the other hemisphere.

The positive feedback in the media

Fine, so this is another paper by which certain "researchers" abuse the confusion of a brainwashed part of the society that wants to hear new and new "horror stories" about climate change. But what I want to analyze is the dynamics by which this still relatively innocent paper gets amplified by the sensational and politically correct media.

The first point to notice is that the media pick the "sensational" parts of the papers only. More seriously, they create titles that heavily overstate the text of their own articles. So the titles of the articles we mentioned at the beginning are:

• Warming pushes bushed birds to migrate farther
  
• Birds face longer migrations due to climate change
  
• Migrating birds have to fly 250 miles further due to climate change
  

Note that none of them makes it clear that the claimed change only affects some birds, according to the article. More seriously, none of the titles makes it clear that the statement is actually a hypothetical projection attempting to describe the years 2071-2100 - about the far future - rather than an observation of reality.

Obviously, many journalists in less important media outlets are not reading other articles too carefully; they don't have to. Some of them only read the titles in their entirety - so guess what their readers and listeners "learn". In the Czech Republic, almost no one cares about global warming. But there are journalists who translate similar reports, anyway.

The first one was Mr Hana Kracíková from Radio Impuls. Here is her article:

Migratory birds confirm warming

Czech president klaus [spelled with lowercase "k"] is short on the migratory birds [they outfox him; "we're short on the birds" is also a well-known Czech song]. They deny his words about the non-existence of climate change. Ornithologists at British universities have noticed that they have moved their breeding places further to the North because the continent is getting warmer. Because of that, some feather guys [birds] have flown by 400 kilometers more than they did in the past.

Suddenly, the birds have already moved their breeding places: welcome to the year 2100, as predicted by the IPCC.

Update I: I've asked her, and she just took it down. Maybe I have used a cannon against an ant. ;-)

Update II: After some time, she has returned the lies on their website.

At any rate, you can see that the distortion industry of this "science" has many layers. Each single of them makes the situation "more alarming".

First, the researchers try to write similar articles because the hypothetical bad effects of "climate change" are a hot topic that some people want to hear: so such work will be funded, approved, accepted, and it will be feeding the writers. Without this portion of the bias, the article would have never been written. Needless to say, the qualitative goals are predetermined: something bad is going on, isn't it?

Second, their article is chosen - out of many other articles that are being published every day and that describe "less alarming" science - by the top-tier journalists because it is a hot topic for them.

Third, these journalists deliberately invent misleading titles that overstate the hypothetical threats and that completely hide that the threats are speculations about the future, not observations of the present.

Fourth, other journalists from less important outlets expand these titles by the top-tier journalists to full-fledged articles that are misleading and untrue even in the bulk. They add unjustifiable comments about birds outsmarting President Klaus, too. ;-)

Fifth, be sure that many stupid people read or hear this stuff and they inform their families that all the birds will go extinct this year. :-)

This is roughly how it works and the distorting filters are so powerful and so numerous that what most of the families in the society hear has nothing whatsoever to do with the reality.

And that's the memo.

GISS: March 2009 was the coolest March in this century

GISS data for March 2009 are out. With the global anomaly of 0.47 °C, March 2009 is reported as the coldest March since 2000 - and colder than March 1990 and 1998, despite the ending La Nina that is being superseded by ENSO-neutral conditions. That puts March 2009 out of the "top ten".

Also, the March 2009 global mean temperature differed by 0.03 °C only from the March 1981 figure - from a month when the ENSO/ONI index was pretty much equal to the current value. This cherry-picked monthly comparison would suggest that there may have been 0.03 °C of warming in 30 years.

See also the corresponding satellite data for March 2009 that were released previously.

The Sun has been spotless for 39 days, resembling the spotless streaks before the Dalton minimum that occurred 200 years ago.

The Antarctic sea ice area anomaly is approximately +1.2 million squared kilometers (more ice than what is normal for the season), almost matching the peak reached in June 2008. Combined with a minor negative Northern sea ice area anomaly, the global sea ice area anomaly approaches huge +1.0 million squared kilometers.



Pen Hadow, the global warming alarmist in the Arctic Ocean, was humbled by the freezing weather and according to BBC, he admitted that "it's never wise to imagine that either man or technology has the upper hand in the natural world."

He said it's truly "brutal" out there - a "constant reminder that Mother Nature always has the final say". He said these words after the team had to abandon Sprite, a key yellow scientific gadget, that froze and broke again, even after it was repaired in London.

According to our poll, 97% of the 400+ voting readers think that they won't reach the North Pole: 57% of them think that they will be dramatically evacuated while 16% think that at least one of the team members will perish.

The explorers may pray that those 16% of the readers are wrong and that Mother Nature, the world's most unabashed denier of man-made climate change who is going to have the final say, allows them to survive despite their arrogant previous proclamations about man-made climate change.

Yesterday, Ann Daniels was lucky: she didn't drown twice, despite the high odds. Also, the organizers hate the climate skeptics so much that they gave Pen Hadow an antiseptic cream instead of a tooth paste. He almost used it.

Against the religion of chaos

One of the irrational misconceptions that I have considered to be dead but that have re-appeared in many recent interactions of mine is the idea that "nonlinear" and "chaotic" phenomena are cool while "linear" and "predictable" phenomena are unimaginative.

For many people, it is enough to say these adjectives if they want to feel smarter. Well, they also look smarter, but only in the eyes of other people whose mental abilities are equally limited. If you open the famous hoax paper by Alan Sokal from 1996,

Transgressing the Boundaries: Towards a Transformative Hermeneutics of Quantum Gravity

that managed to be published by some pompous fools in the "Social Text" magazine, even though it is a long and manifestly fake sequence of ludicrous absurdities, you will see that the word "nonlinear" appears more than 20 times over there, and so does the word "chaos". They're combined in sentences showing the immense pride of the fictitious author, Alan Sokal, or real, dumb authors who are being cited by Sokal.

Steven Weinberg was amused and has reviewed Sokal's prank. Weinberg notices that the postmodernists use the words "quantum mechanics" and "chaos theory" to promote their ideas about the fragmentary nature of experience. Also, in this framework, "catastrophe theory" and "chaos theory" lead to social and economic liberation, Weinberg says. Yes, "catastrophe theory" is about the tipping points, the critical parameters in bifurcation theory.

Concerning the word "nonlinear", Weinberg has observed pretty much the same thing as I have written many times:

But for some postmodern intellectuals, "linear" has come to mean unimaginative and old-fashioned, while "nonlinear" is understood to be somehow perceptive and avant garde. In arguing for the cultural importance of the quantum theory of gravitation, Sokal refers to the gravitational field in this theory as "a noncommuting (and hence nonlinear) operator." Here "hence" is ridiculous; "noncommuting" does not imply "nonlinear," and in fact quantum mechanics deals with things that are both noncommuting and linear.

Well, the postmodernists - and unfortunately not only the "official ones" - like to use the words such as "chaos", "nonlinear", and "noncommutative" as synonyma. These are the words that they "endorse", regardless of the meaning, and such an endorsement makes them "cool" in their own eyes and in the eyes of their "peers".

Needless to say, this whole line of reasoning is irrational crap. These words are not equivalent and they are not "sexy" per se: only interesting, true, and non-trivial sentences combining these words and other words may be intriguing or stunning. And there's nothing generally "boring" about the words "linear" or "commuting", either.

Linear things are often cool

In fact, quantum mechanics, the most important insight of the 20th century science, implies that all observables (such as position, velocity, magnetic field, or spin) are linked to "operators", mathematical objects that are both noncommuting and linear. (There also exist objects that are nonlinear and commuting.) All the evolution in quantum mechanics is described by a linear equation (e.g. Schrödinger's equation in the corresponding picture).

This general proposition about Nature, much like the other basic postulates of quantum mechanics, seems to hold exactly and there are good reasons to expect that nothing will ever change about these basic rules of Nature. The inevitability of the quantum postulates has been partially demonstrated and all attempts to circumvent the principles proposed as of today have been ruled out, either theoretically or empirically.

Quantum mechanics is linear but there are many concrete situations - and approximate descriptions - in science that use linear dynamics in a very important way to obtain very profound results. It's not hard to see that virtually all classical dynamical laws seen in Nature and the society are nonlinear. The linear laws are of measure zero, as long as one adopts any continuous measure that covers both linear and nonlinear objects. But the linear laws and operators still exist and they may be very important. In many cases, they are more important than the nonlinear ones.

The "confusing", "unpredictable", and "chaotic" character of the observation seems to be the default state. This is the state of knowledge we have about any system that we haven't yet understood. There is nothing shocking about this state of ignorance - it's the standard situation. Interesting science only begins once we start to see patterns, regularities, and predictable features with nonzero information.

In this sense, I disagree that "chaos theory" belongs among the most important developments of the 20th century science. The methods of "linearization" have arguably been much more useful and led to more extensive and profound results than "chaos theory". In a related context, "perturbative" vs "nonperturbative", it could have been a tie even though the "perturbative" part of science has been much more accurately confirmed by experiments (QED...).

The very observation that complex enough systems are generically chaotic - i.e. that they sensitively depend on the initial conditions - seems to be completely obvious. I don't believe that Isaac Newton would have been surprised by such things. In his era, people simply focused on simple enough systems that they had a chance to solve or approximately solve, and that was a very wise decision.

But if one considers systems with many degrees of freedom - e.g. a real gas composed out of many atoms that Ludwig Boltzmann had to consider in his atomic picture of the world - it is completely clear that the microscopic details will be effectively unpredictable. The result of each collision depends on the detailed initial positions and velocities (imagine that you shoot a planet against the Sun and study where it deflects) and the large number of collisions "thermalizes" the initial information much more rapidly: the entropy keeps on increasing, after all.

All these statements can be seen to hold within minutes, one doesn't have to be a PhD to see why. And at a general level, that's pretty much the end of the story. I don't understand in what sense this "discipline" may be equally important as e.g. atomic theory (based on quantum mechanics) or the relativistic description of black holes. It is surely not equally far-reaching or extensive.

And what's much worse, the existence of "chaos" in various theoretical models (think of the atmospheric or climate models) is often incorrectly assumed to be sufficient for these models to be right. Well, the (non-)existence of chaos carries at most one bit of information which is surely not enough to verify a hypothesis. Much more specific, quantitative, "non-chaotic" tests are needed to do so.

Is the world chaotic?

Well, the world is exactly described by quantum mechanics whose state vector is governed by a linear law. Because the Hamiltonian is Hermitian and/or the evolution is unitary, it follows that the distances between the initial states will not be modified by the evolution at all. That's what unitarity means: a unitary operator is just a complex "rotation" that doesn't change the distances in the (Hilbert) space. Unitarity of our quantum world makes the whole world completely non-chaotic in the classical sense. The chaotic behavior only emerges in a classical description - if you pick some particular classical observables and the "distance between configurations" based on these observables.

That doesn't mean that there is nothing deserving the word "chaos" in a quantum theory: "quantum chaos" has become a whole subdiscipline of quantum physics. It studies the complicated spectra and eigenstates of various Hamiltonians whose existence is linked to the appearance of chaotic (initial-condition-sensitive and otherwise unpredictable) behavior in the classical limit.

But yes, quantum mechanics implies that some conclusions about the "chaotic behavior" are mere artifacts of the classical approximation. Moreover, every system with a finite phase space - or every quantum system with a finite-dimensional Hilbert space - exhibits the Poincaré recurrences. They imply that the "asymptotic behavior in the far future" used to define some concepts in chaos theory (those where one assumes that the number of degrees of freedom is infinite) cannot be taken literally.

But again, what I find most unscientific in this ideological framework is the idea that the foggy word "chaos" should ever be the end of the story. Many things in Nature look incomprehensible at the beginning. But the more we study them, the more we learn. Various outcomes may look "random" but there is not just one kind of "randomness". Every set of random data in Nature follows some statistical distribution. In every context, this statistical distribution may be, in principle, found - both by experimental and theoretical methods.

The overall distribution for one quantity may be a big victory relatively to the complete ignorance but it doesn't have to be the last word, either. One can try to measure and/or calculate more complicated correlations, too. Even in the absence of a detailed knowledge about the microstates and their evolution, one can ask new well-defined questions (e.g. statistical questions) about this evolution. With a sufficient effort, one can answer them, too.

One can assign the word "chaos" with specific meanings but any meaning of this sort removes the fog from the word and makes it relatively mundane or even uninteresting. For example, whole classes of theories can be instantly proved to increase/decrease the size of the initial perturbations. Many theories and situations may be exactly solved while many more don't have a compact solution - even though this statement is, once again, not terribly interesting because it depends on the inevitably non-canonical definition of a "compact solution". Which functions are allowed to appear in a compact solution? There is clearly no universal answer to this question.

If "chaos theory" is supposed to be long-lived - to be more than just a simple problem to find the sign of a Lyapunov exponent - it must dynamically change the meaning of the chaos as we are learning additional things. That's why there exists a complementarity - the discipline is uninteresting whenever it is sharply defined and it is vague whenever it has a chance to become interesting.

Many fragmented pieces of knowledge are being incorporated to "chaos theory". For example, complicated systems often exhibit a self-similar, fractal behavior. Again, this is not hard to understand if the effective laws describing the situation are recursive (like in the case of the Mandelbrot set) or scale-invariant (like in conformal field theories). In the latter case, we often care about the scaling exponents.

For example, the primary fields in the Ising model have dimensions 0, 1/2, and 1/16. The third one looks pretty complicated - and be sure that it describes a feature of some self-similar pictures of situations involving many small magnets, among other things. Is this result, 1/16, supposed to be a part of chaos? Well, the simplest derivation I am familiar with doesn't look chaotic in any way. You can get it as the difference between the ground state energies in the periodic and antiperiodic sectors of a fermion.

Because 1+2+3+.... = -1/12 while 0.5+1.5+2.5+... = +1/24, their difference is 3/24=1/8 for a complex fermion (without 1/2 for the ground state energies) i.e. 1/16 for a real fermion. If someone suffers from the zeta-regularization-phobia, the argument can be easily modified to avoid any divergent sums while the result is guaranteed to be equal: study various exponents and factors in the modular functions. Is there something "chaotic" about these derivations?

I don't see it. I don't understand how such derivations could be separated from conventional theoretical physics - in this case, from conformal field theory - and how could they deserve a natural umbrella of a new discipline. The state-operator correspondence (annulus vs cylinder map) has been used and it is very deep and "non-chaotic". And it sounds very counterproductive if someone would like to suppress all these deep methods in his attempt to preserve the "chaotic image" of a system that can actually be understood by proper, predictable, calculable science.

I could give you many more examples of this phenomenon. For example, "attractor points" belong to "chaos theory". But it is clear that the clearer, more transparent, more conceptually organized, and more brilliant derivation of the attractor points and their properties we find (think about the derivations of the attractor mechanism affecting black holes in supergravity, issues that were recently very active in string theory), the less chaotic the whole set of phenomena looks.

What makes certain insights ready to be included into a new discipline called "chaos theory" is precisely the fogginess of their existing description - and this is surely not a feature that should justify the creation of a new discipline. Let me apologize to the readers-believers in advance and explain why I have used the word "religion" in the title. The reason is that this "worshipping of chaos" has the same internal logic as religion. As Feynman said:

God was invented to explain mystery. God is always invented to explain those things that you do not understand. Now, when you finally discover how something works, you get some laws which you're taking away from God; you don't need him anymore. But you need him for the other mysteries. So therefore you leave him to create the universe because we haven't figured that out yet; you need him for understanding those things which you don't believe the laws will explain, such as consciousness, or why you only live to a certain length of time -- life and death -- stuff like that. God is always associated with those things that you do not understand. Therefore I don't think that the laws can be considered to be like God because they have been figured out.

By the way, I am not the first person who invented the religion of chaos. It has been around for some time and it is also called discordianism. There's no consensus whether this religion is real or just a parody. ;-) By the way, one of the important practices of this religion is Operation Mindfuck which is often manifested as civil disobedience, activism, trolling, and other things. It may explain a lot!

Summary

In real science, it is impossible to impress rational people just by repeating some words often. It would be great if the postmodernists ultimately understood this principle. Meanwhile, it seems that the opposite dynamics is taking place - that many people are effectively becoming postmodernists. Sokal's hoax is so similar to the contemporary writing by so many people - including those who claim to like physics - that I am skeptical about the dynamics of the society. The evolution seems to lack the proper selection mechanisms and it is becoming pretty, ehm, chaotic.

And that's the memo.

The Hofstadter Isotope

Episode 2x20 of The Big Bang Theory:

Watch it (click)

Penny with a guy (not quite) just like Leonard, namely Stuart from the Comic Book Store...

Stolen Kosovo: a TV documentary

Video 1: Ten parts of the documentary, including English subtitles.

This one-hour Czech TV documentary shows a lot of touching details about the violence against the Serbs and their culture in their historical province of Kosovo and Metohija (Kosmet) - by the Nazis, communists, and the Albanian terrorists silently tolerated (and sometimes openly supported) by some NATO members.

It's a very sad story and how can someone side with the KLA against the Serbs is just beyond me.

Meanwhile, Serbia is getting ready to send the 300-page complaint against the declared independence of the province to the International Court of Justice. Also, BBC has just revealed the horrors of KLA prison camps.

Armed gangs and organized criminals flee to Kosovo every day, for example the bank robbers today, because they know that Kosovo is now officially governed by their colleagues so they're pretty safe over there.

At the same moment, the five-day-old protests to oust the president of Georgia intensify. The protesters are dissatisfied with his record on democracy and the disastrously ill-conceived war against Russia.

King Coal Carlsbad wins Czech ice-hockey extraleague

At the end, Pilsen lost to Slavia Prague in the semifinals. However, our Western Bohemian rivals from Carlsbad, the well-known spa town (hotels), managed to defeat Slavia Prague in the finals. In the decisive match, they transformed a hopeless 0:3 score to 4:3. The Carlsbad players are nicknamed "the Russian bitches" by the melodic Pilsner fans, due to a high influence of Russian businessmen in that town.

The sponsor of HC Energy Carlsbad are the unions at Sokolovská Uhelná, the brown coal joint stock company from the nearby town of Sokolov. It produces 10 million tons of brown coal annually. While it used to be the symbol of the degradation of the environment near the Czech-EastGerman border during communism, it became one of the Czech companies with the highest investments to green technologies (not only the players' outfits): 4.5 billion CZK since 1994 (USD 1 = CZK 20 today).

Ore Mountains have been regaining their health for quite some time. Even though the local brown coal contains a lot of toxic stuff, including uranium, the company seems to be pretty clean these days - unless you're one of the loons who consider CO2 a pollutant.

Yuri Gagarin: 48th anniversary

Honor to the Astronaut (click)

(Jaromír Hnilička / Pavel Pácl,
translation L.M., sung by Gustav Brom 4/12/1961)

The whole world heard the news from the Soviets,
the whole world suspended all its chats.
The whole world jumped away from radios,
and it turned all its eyes to the skies.

Good morning, Mr major Gagarin,
we couldn't wait but now it is here.
The whole world drank wine red as your flag,
people were waving all of their hands.

2x Tell the guys who live on the stars,
tell the guys who live on the Moon.
Tell them the message from us humans,
that we will follow your steps soon.

I can't sing this fun song terribly well
because my voice is trembling like mad.
I have heard that you are twenty seven
and the world is as young as you are.

(In the translation, "Soviets" was chosen instead of "TASS", the Press Agency of the Soviet Union. I've exchanged "stars" and "Moon" to make "Moon" rhyme with "soon". Some articles were omitted to fit the syllables.)

See also the amusing 2007 update of this song, supporting the U.S. missile defense system radar in forests near Pilsen and sung by our minister of defense and her fellow musician. ;-)

Hat tip: Dmitry Podolsky

Pen Hadow's scientific expedition disintegrating

This page contains a poll about their fate...

Pen Hadow and two companions want to get to the North Pole and supply the Copenhagen conference with the required "doomsday data" to ban carbon, the main hallmark element of life, on Earth.



Gadgets break down

However, as BBC informed on Thursday, the scientific gadgets, including radar device Sprite and salinity/thermometer SeaCat, keep on malfunctioning. The technology failed largely due to "unexpected" (by them) minus 70 °C wind chill. At least, they can regularly drill the ice. :-)

On the fifth day of the expedition, one cable simply snapped. Four days later, it was clear that this made all the cables break. So out of the first 18 days, Sprite only collected data from 7 hours. :-) They were trying to fix the radar and/or give them a new one.

Update: As expected, Sprite continued to malfunction after the repairs and it was abandoned on day 44. Hadow conceded that Mother Nature always has the final say.

Biometric data are fake

It was also realized that the body temperature data on their website are completely fake. Click the first link of the previous sentence and be sure that Hadow's core temperature will be 33.25 °C at the beginning, rising by pre-determined steps to 33.75 °C or so. All the other temperatures on their page are pre-programmed, too - a method that is rather characteristic for the "global warming research".

(The page was later updated: it says that the pre-programmed biometry data were recorded on March 8th. I would doubt this more modest statement, too.)

Sadly, the page with the current conditions (click the "body temperature" link above) tells us that today in the morning, Ann Daniels spent several hours by "sitting at" and pre-heating a dead battery from the previous day instead of the correct, fresh one. ;-) On the positive side, she could finally throw away her sledging jacket for some time, one of the 15 or so pieces of clothes she wears.



Picture by Anthony Watts. Shift/click to zoom in in another window.

Will they get there at all?

There also exist serious doubts whether the expedition can get to the North Pole at all. See Steve Goddard's text. After 40 days, they have only made 240 kilometers. April 30th is the last day to recover the people safely from the North Pole region so they have roughly 20 days for the remaining 685.61 kilometers (as of today: yes, this figure actually increased by 2 km from Friday). As the summer is approaching, the areas with missing ice should start to spread.

But I personally don't expect Hadow to care about the safety of the airplanes much: he has already been evacuated from the North Pole in late May of 2003. Airplanes sometimes sink near the North Pole in May - and sometimes all the people are saved.

Thirty-five kilometers per day wouldn't be that hard for OK athletes. But these people may be exhausted, mostly due to their terrible planning. I wish them good luck - but not necessarily miraculously great luck! ;-)

Here's a poll. The only reason I didn't use JS-Kit polls for quite some time was that I forgot that I had to reset admin access after some time and it didn't work without it.

Bonus: walrus has some trouble



Because a few days ago, the Arctic team saw the carbon footprints of the local landlord, a male polar bear whose private territory they have violated, they may want to watch the video above to improve their mood. ;-)

Here is how a polar bear chooses inside a team of walruses. And another video shows how a seal needs some air. Bad luck.

Whistleblowers at the Perimeter Institute

A former director of the Perimeter Institute has written a text - that will be explicitly promoted neither on TRF nor in the comments - about the insane beginnings of the Perimeter Institute for theoretical physics. The readers can see how easy it can be to suck money out of an impressionable, idealistic, and generous billionaire - in this case Mike Lazaridis.



Off-topic: Little red riding hood with technical documentation. ;-)

Nemanja Kaloper (UC Davis) is a very serious phenomenologist, with roughly 100 technical publications in particle phenomenology. He has had many students. But for one of them, who was just a de facto student of Nemanja because Nemanja was still just a postdoc at that time, the PhD defense in 1998 was the maximum that Nemanja could have hoped for. At the end, this student managed to co-author two very similar 15-page papers. One year after the defense, this "doctor of physics" received his first citation. The total score is eight citations as of today.

Let me call this not-exactly-stellar student Wolowitz Richter. ;-) He didn't like string theory but he did like money.

Now, you should understand that Nemanja's opinions about string theory are somewhat neutral. Like other phenomenologists, he realizes that it is likely to be the only possible theory in the deep ultraviolet. But more importantly for him, it leads to some phenomenologically interesting ideas for low-energy physics. Nemanja often combines them with other ideas about low-energy particle phenomenology that he can find by other methods. And he simply uses whatever he can to find some interesting new results.

OK, the student, Wolowitz Richter, who just defended his PhD, was very different. His dogmatic dislike for string theory (and probably any other well-developed machinery where people have to work somewhat seriously to find something new and equally meaningful) and his positive attitude to wealth could have been combined. After some negotiations, Lazaridis - eager to do something really crazy - made him the director of the Perimeter Institute, the world's main institute for theoretical physics among those that are funded primarily by the private sector. Wow.

Of course, such an anomalous situation couldn't last because it is bizarre to have an irrelevant scientific zero as the chair of an institute whose name and generosity has been memorized after a few years, so Neil Turok was recently chosen to replace interim boss Rob Myers and to be the new director. Before Wolowitz Richter was fired, he managed to write a public text that exposes pretty much all the business (and personal) secrets of the Perimeter Institute. He wants to earn money by publishing this sensitive stuff. It's not the kind of guy whom you want to trust or pay if you're a billionaire.

It's not the kind of guy whom you want to pay if you're anyone, after all.

Choosing hiring strategies

But what I want to discuss is the hypothesis that one can create systematically good results just by being "against the establishment".

That's, of course, nonsense. Only positive plans, ideas, knowledge, skills, good luck, and hard work can systematically lead to positive outcomes. They often turn out to be "anti-establishment" in one sense or another - because the establishment is often wrong - but this "contrarian" feature of theirs cannot be their definition.

Every establishment has problems but unless it is completely screwed - and I am sure that most of you agree that the physics establishment is not (or, at least, it wasn't in 1998) - it includes certain "natural selection" mechanisms that choose better things and abandon worse things, at least statistically in the long run. If your strategy is to be choosing the opposite things, without knowing any positive reasons, your results will surely be worse than with a "neutral approach".

Let us imagine that much like the companies want to maximize their profits, physics departments want to maximize the overall importance of the scientific results that will be found there.

Now, the detailed strategies of different companies - and different physics departments - differ. But each of them has to follow some semi-consistent guiding principles based on some positive values. One place can prefer powerful mathematicians, another place can prefer people who can think quickly, the third place may collect people who are good communicators, the fourth place may prefer researchers whose knowledge is extraordinarily broad or versatile, the fifth place may like experienced people who have already achieved something, while the sixth place may try to estimate the growth potential of those who are not yet achieved or famous.

One coast may consider cosmology or the anthropic principle paramount while another coast may prefer the detailed spectra of quantum field theories or anything else.

There is clearly no universal rule that would tell us what is the importance of all these values and ideas. There is no formula that would calculate the success as a function of these things. We are obviously talking about an uncertain business with too many unknowns. But the strategy to do "anything" as long as it is different than what others do is obviously inferior to almost all the other strategies.

In some general sense, physics departments or any other meaningful departments must approach the hiring and related problems in the same way - a way based on meritocracy (much like the companies that always want to maximize the profit). They just quantitatively differ in their appraisal of the value of different ideas and skills (again, this has analogies in the conventional markets). Clearly, you can't be doing just the things that are considered to be trash by everyone else - without knowing why it has a chance not to be trash - simply because most things that are being thrown away are trash, indeed. You can't pay millions for excrements, hoping that you will benefit because others are surely making a mistake.

In the short run, there are so many random effects and so many questions remain uncertain that the detailed strategy can't be observationally evaluated. Moreover, directors are not that important for physics institutes, anyway. But be sure that in the long run, a bad strategy will lead to bad results.

Imagine that you decide that everyone else undervalues a research direction - for example Acausal Kinematical Rectangulation (AKR). Well, if you rely on this sociological guess and you have no technical reasons for your belief, that's quite a bet. The probability that everyone else actually overestimates AKR are equal to the chances that they underestimate it. Although some people may fool themselves into believing otherwise, there can't ever exist any a priori knowledge about the question whether a product or a small group is undervalued or overpriced.

The conventional meritocratic places that follow one prescription or another are analogous to different types of value investors. A new place that is defined by its desire to be "anti-establishment" is a counterpart of a hedge fund, but a very unsophisticated one. More sophisticated traders can actually calculate the imperfections of other traders. Many of those are doing the same thing so the winners and losers are pretty much matters of chance.

But don't forget about one thing: while the other traders follow various strategies and counter-strategies that may resemble a lottery, a part of their decisions is always about a legitimate, meritocratic, value-based evaluation of the assets. So if you bet against everyone else, without making any more detailed calculations, you will statistically lose.

Let me admit that I am highly surprised by the currently popular desire to encourage the risk and to buy "risky assets" in physics. That happens despite the fact that we are just seeing where such an irresponsible behavior led in the case of the market with derivatives and similar stuff.

But what I find even crazier is the ability of many people to believe that the people who are actually the textbook examples of the problems with the current - and emergent - establishment are also the people who may bring "fresh ideas" and who have shown the courage to run against the wind.

Instead, they are self-promoting, slow, lazy, inefficient parasites. I am talking about all those male and female feminists and similar dishonest low-quality groups that complain that they are still not getting enough - even though they have pretty much flooded and contaminated all of Academia and they are already deciding about the fate of all employees including the university presidents.

If you're a billionaire, be sure that if you want to look for original people who can run against the wind and who are underrated, by orders of magnitude, by the status quo, you must look somewhere almost exactly in the opposite direction than what this politically correct pseudointellectual foam is instructing you to do.

And that's the memo.

Donagi, Wijnholt: what 3 generations mean in F-theory

The best hep-th paper today is the second one,

Higgs bundles and UV completion in F-Theory (PDF)

Ron Donagi and Martijn Wijnholt look at the F-theoretical model building. As the first true professionals, these Gentlemen seriously study the question whether the models may have three generations and what it means. You can see that each segment of their writing that you read in detail seems to make sense, unlike some attempts that have tried to answer similar questions and that required many "clouds" saying that "here a miracle occurs".

Recall that in the local F-theory model building, the gauge groups are carried by real codimension two objects, i.e. by seven-branes of type IIB string theory. Such objects can carry exceptional symmetries, up to E_8 itself. In other words, the gauge theory is supported by a 7+1-dimensional spacetime manifold.

Three generations make things special

Donagi and Wijnholt realize that the compactifications - on Del Pezzo-like real-four-dimensional manifolds - are given by meromorphic Sl(5,C) Higgs bundles. The latter can be mapped to spectral covers in an auxiliary Calabi-Yau geometry. For generic moduli, they can practically prove that there can't exist any three-generation models. That's actually a good thing because these models wouldn't stabilize the moduli and the proton decay could be rapid.

Instead, they claim that there exist special points in the moduli space that solve a condition that mathematicians would refer to as the Lefschetz-Noether (LN) problem. At this LN locus, there actually exist new fluxes that can be turned on without breaking the supersymmetry. With these additional conditions satisfied, some moduli are automatically stabilized.

Interestingly enough, these "new fluxes" at the special points can't be inherited from the bulk which also means that these F-theory compactifications don't have ordinary heterotic duals. Analogous degrees of freedom actually do appear on the heterotic side, in the form of rigid bundles (I guess that they could be analogous to the "triples" by the seven authors), but they haven't been studied much so far.

This missing ingredient is one of the reasons why the heterotic model building as of today has mostly overlooked the bulk of the large type IIB landscape. ;-) While they can obtain three generations, the models they see by their method contain some exotic matter. Reduction of the spectrum is arguably equivalent to another layer of a Lefschetz-Noether problem and will probably stabilize additional moduli. Some mathematical tools to do so will have to be developed.

General message

At any rate, this is a great line of reasoning that would be completely overlooked by the "anything goes" anthropic pundits. By postulating that we will never learn anything new about the relationships between the properties of the real world as we know them from the existing low-energy effective theories, they would make it impossible to figure out how constraining the three generations are and how this number "three" is related to the stabilization of moduli, to the existence of dual descriptions, and to the choice of special solutions.

It seems very plausible to me that in the future, people will be able to show that a model with a hierarchy is essentially unique. The more papers of this kind I see, the more I am inclined to think that our Universe is very special. I am also aware of papers suggesting that our vacuum is rather generic but these papers seem more philosophical and "circular" and less analytical.

The gravity-electroweak gap may guarantee that the local reasoning (and perhaps the F-theoretical local reasoning) is legitimate, the local reasoning may imply that three generations and stable protons require us to solve the most constraining Lefschetz-Noether problem one can think of, and the solution to this problem may be unique, much like the global extension of the local model found in this way.

Whether this is the case or not can only be found by a careful and patient analysis of these exciting classes of models and by seriously considering all known symmetries, discrete parameters, and hierarchies.

And that's the memo.

Friday F-theory phenomenological papers

The F-theory phenomenological minirevolution continued on Friday, too. But one has to look at the hep-ph archive. Bouchard, Heckman, Seo, and Vafa study the dependence of fermion masses on the GUT coupling: it's different for quarks and for neutral leptons. The different hierarchical patterns seems to agree with the observations.

Randall and Simmons-Duffin, also of Harvard, also look at flavor physics in F-theory and interpret it perturbatively within an effective theory.

Holdren: I will return us to the Age of Smog

As AP and others reported, Obama's science advisor John Holdren wants to reintroduce smog to the atmosphere.

The reason is that by living in the age of global warming, we are driving a car with bad brakes toward a cliff in the fog. He repeated this "rigorous" sentence twice in 30 minutes. ;-)

Well, it's clear that if we ever had a problem, all options would have to be considered, and this set of strategies would be a natural one to manipulate with the temperature. It would probably be cheaper than fossil fuel caps by orders of magnitude, too.

However, it is strikingly obvious that there doesn't exist a tiniest sign of a negative consequence of the hypothetical global warming. So why would we be returning to those dirty times?

In Communism, capitalism, and environment, I explained how horrible the pollution used to be in the industrial communist cities. We were not talking about CO2 which is a completely innocent gas - but about SO2, SO3, NOx, CO, NH3, ozone, particulate carbon, and similar stuff. Children began to be slightly sick. Acid rains were killing forests. Weeks of schooling outside the cities had to become mandatory.



Ore Mountains (Erzgebirge / Krušné hory) on the heavily industrialized EastGerman-Czech border at the end of the 1980s (the end of the communist era). Acid rains did the job. Today, the mountains are thriving again.

Capitalism cured all these things. People didn't want to live in a contaminated environment and they actually became able to influence whether their environment is healthy. Unnecessarily dirty technologies - whose main goal was to fulfill communists' arbitrary and absurd 5-year plans - have disappeared, useless portions of the heavy industry were reduced, affordable gadgets to clean the air coming out of plans could have been bought, and the pollution decreased by an order of magnitude.

By its characteristic partial steps, capitalism automatically and naturally increased the concentration of technologies and habits that were mostly useful for the humans - and others whom humans care about - and reduced those that were harmful.

It is not surprising that this striking contrast between capitalism and communism may work in the reverse, too. When a hardcore 19th-century-style communist becomes too powerful in a previously advanced and healthy capitalist country, it may indeed become possible to transform the country into an underdeveloped polluted communist chimney.

It is clear to me that some people should be thinking about the causal mechanisms in the atmosphere and the possible technologies to influence the climate and/or the weather, in one way or another. But we should actually be comparing the costs and benefits. A dirty atmosphere is surely much worse than half a degree Celsius of an additional warming. Even five degrees Celsius would be more pleasant than the return to the decades of smog, to the age of relatively unknown chemicals and particulate matter filling the atmosphere. In fact, five degrees Celsius of warming could be better than nothing, too.

The idea that we should actually be using similar technologies at a global scale in the next 20 years or so is utterly absurd. There is no problematic global warming, it is far from clear whether the climate will be warming in the next 20 years, there are no tipping points, there are no critical values of the CO2 concentrations where problems suddenly begin - all these concepts are just fantasies being invented to spread fear among the stupid people, to promote dirty chimney communism, and to increase the power of those who want to return us back to the 19th century and beyond.

And that's the memo.

New Scientist about Edward Witten

Matthew Chalmers wrote a pretty good article about Edward Witten for Nude Socialist:

Inside the tangled world of string theory (click)

It tells you that despite being a Witten, Witten received a lousy office from CERN. That's called the European hospitality. ;-) To be fair and balanced, you should also look at Einstein's office at the IAS in Princeton.

Witten considers the "string wars" that began in 2006 by the publication of two books by Swolin (that he hasn't read) to be as irrelevant episodes as the short-lived chaos initiated by the publication of a similar book, The End of Science, by a similar "thinker" a decade earlier. Neither of the books nor the temporary nature of their repercussions - Swoit's 15 minutes of fame - reflected any change of the underlying climate, Witten enunciates.

The following paragraphs sketch Witten's opinion about the interpretation of the landscape, the multiverse, the expectations from the LHC, extra dimensions, supersymmetry, Witten's favorite sports, Witten and history, advantages of Witten relatively to Einstein and vice versa, and many other things. Chiara Nappi believes that top physics can no longer be investigated in a patent office in Bern, Switzerland. It can only be pursued in a latent office in CERN, Switzerland. ;-)

Finally, Matthew Chalmers informs the readers that after 339 articles and 87,000 citations, Witten (and his wife) may finally start some serious work because their children have moved out. ;-) Well, let's hope that those 33 years of the relative silence described in the previous sentence will be replaced by some genuine explosion of ideas! And let's hope that our brains won't explode along the way.

Richard Feynman on gravity

The Messenger Lecture about The Law of Gravitation:

Playlist (click, 7 x 8 minutes, play all)

The first minute is black. Then the Cornell Provost introduces RPF in the first part: the lecture takes place in 1964 when Feynman was already happy at Caltech.

In the first part and the early second part, he explains why science is superior over social science and why he would focus on Nature rather than Man. Tycho de Brahe is quoted as the originator of science: his idea was to record the observed positions so accurately that different detailed hypotheses could be compared and/or excluded.

The third part is already dedicated to Kepler's laws. He mentions some theories of that time - that angels were pushing the planets. The theories were almost right, RPF says, except that the angels are actually sitting on another side and are pushing the planets radially. :-)

Applause follows. Of course, the discussion turns to Galileo and inertia. Newton added the forces that can change the straight lines to different paths. The universal law of gravity evolves naturally. A lot of dramatic predictions were made - parameters of orbits, tides, etc. High-precision tests followed: the moons of Jupiter. The first discrepancies (moons ahead of the schedule) were explained by the finite speed of light.

In the fourth part, he explains more examples how new laws can be found by taking the old ones serious: the Neptune was predicted and discovered by the 2nd observatory (that didn't share the arrogant and dumb anti-theorist attitude of the 1st one). ;-) Finally, the Mercury anomalies were fixed by Einstein.

The fifth part discusses how gravity holds clusters of stars together: gravity extends very far. For galaxies, he has no way to check but he has no doubt ;-) that the inverse square law will continue to hold (and no dark matter would be needed haha). Gravity acts on clusters of galaxies, too. Still, gravity doesn't have too many applications, except for scholars' jobs and astrologers. :-) Feynman asks whether he attracts a viewer physically. :-)

In the sixth part, Cavendish-like short-distance tests of gravity are being reviewed. Newton's constant was determined for the first time. Equivalently, the masses of celestial objects - in "small" units from everyday life - were measured. The Eötvös experiments to test the equivalence principle are reviewed. He continues with the electrostatic law that has the same inverse square law and argues that the electro-gravitational unification had not worked so far. The huge discrepancy in their strength (between electrons) is picked as an argument against their unification.

Well, this is pretty much what we call the hierarchy problem these days. The last, seventh part continues with this mystery and suggests that the quintessence solutions don't work. More importantly, he mentions quantum gravity. Feynman says that there was no theory of quantum gravity at that time. He promotes the second lecture, on the link between maths and physics (see the URL below), by suggesting that some people may prefer a "mechanism" over maths.

The laws are often known incompletely. However, Feynman concludes by saying that gravity is pretty because its laws are simple in principle (not necessarily in their manifestations) and universal. Nature only uses the longest strings to weave the patterns. So each small piece of the fabric of the cosmos reveals the organization of the entire tapestry.

And that's the memo.

See also: RPF on the arrow of time, the relationships between maths and physics, fourty-six 1979 lectures, Pleasure of finding things out, and Feynman's 90th birthday where additional links appear.

Correlation of sunspots and sea level

Click to zoom in. Did they ever fit together? Most ridiculous thing I ever heard. :-)

I find this graph by David Archibald stunning. Relevant posts at climate realist websites:

Watts: Archibald posts this graph
Climate Audit: Holgate on sea level
Watts: Sea level and Jason data

The graph shows a remarkably accurate correlation between the number of sun spots - following the approximately 11-year solar cycle - and the annual sea level rise in millimeters.

See pages in Colorado to download the sea level data from satellite altimeters etc. and a previous posting about the sun spots for links to the solar data.

To draw it, Archibald had to calculate the "derivative" of the usual graphs showing the sea level itself, as a function of time (years).



In the real climate, the solar activity seems to influence the sea level rise. As you can see, something is usable out of the ardent & concerned writers' website: the logo.

I would bet that such a tight correlation simply cannot be a coincidence. There's no independent reason for such an accurate "11-year" cycle in the sea levels that would moreover happen to be synchronized with the sun spots. If you know about an alternative explanation of the 11-year cycles in the sea level rise, let me know: I am very curious.

My explanation suggested by the picture is the obvious:

1. a higher solar activity increases the global temperature, probably by shielding the Earth from the cosmic rays that would otherwise create additional cooling clouds
2. the number of cooling clouds is therefore decreasing when the number of sun spots is high, and vice versa; the temperature behaves in the same way with the opposite sign
3. the sea level is the most accurate proxy for the global mean temperature - and especially the non-meteorological and "external" drivers and of it - that we can get; it may automatically subtract some local, internal, meteorological effects such as ENSO; it automatically chooses the right altitudes where the temperature should be measured and averaged, and so on
4. the sea level therefore responds much like the temperature that behaves as explained above
5. its increase therefore directly reflects the solar activity, with almost no lag
6. the additional underlying linear warming trend evident from the rising sea level is caused by much slower effects, especially the glaciation cycles and the enhanced greenhouse effect

This theory seems to make perfect sense to me. But we will have to wait for some time to see whether the correlation and synchronization survives.

At any rate, the Sun seems to have a huge effect. The graph suggests that solar activity changes the annual sea level rise from a minimum around 0 millimeters per year to a maximum around 5 millimeters per year.

The average trend, around 2.5 millimeters per year in the time interval of the graph, is caused by slower effects - including the Milankovitch cycles and the enhanced greenhouse effect. But you can see that the solar activity is as big as all these effects combined.

What I mean by the previous sentence is that if the solar activity drops to zero or near zero, e.g. for two decades, the sea level rise will also be zero or slightly negative, indicating a modest global cooling - regardless of the origin of the slow, currently warming underlying trend.

Needless to say, after some time, the underlying slow processes will switch to cooling, too.

In a few millenia or so, the Earth will naturally begin to return to another ice age. Recall that between 15,000 and 5,000 years ago, the sea level was increasing by more than 1 meter per century (about 100 meters during the period), much faster than today, and a comparable decrease of the sea level may be expected in the opposite parts of the cycles.

When we look at these long-term developments, one must realize that while the sea level may be a great proxy for the global temperature, measuring the external drivers only, the coefficient relating the warming/cooling and the sea level rise is changing after millenia. When there were many more continental glaciers, the sea level arguably responded to the changes of the temperature much more intensely than today - because there was a lot of continental ice ready to melt or grow.

For the most recent 6,000 years or so, essentially only Greenland and Antarctica contributed to the sea level rise by ice melting. The heat expansion of water in the oceans is a contribution to the coefficient that doesn't change much.

Let me say that I do believe that the increasing CO2 concentration does contribute to the slower underlying trend. But it is clearly not the only (or dominant) contribution because the sea levels have been changing equally or more rapidly than they are today, long before we were producing lots of CO2.

Richard Feynman on the arrow of time

The distinction of past and future

Playlist (click, 5 times 10 minutes)

The lecture is pretty much isomorphic to Chapter 46, Volume I, of Feynman's lectures on physics.

The lecture took place a few days after the experiment finding the CP violation. Feynman was somewhat skeptical ;-) but he correctly said that the effect couldn't be responsible for the macroscopic irreversibility.

In the first part, Feynman talks about the reversibility of the microscopic laws, the irreversibility of all macroscopic phenomena, and the need "not to look too carefully" in order to understand the irreversibility.

In the second part, he gets to the low initial entropy. At the end of this part, he suggests the "Boltzmann brain" theory. At the beginning of the third part, he explains why this is a "ridiculous theory" because it incorrectly predicts that the rest of the world should be completely disordered.

He also explains that the low initial entropy is independent of the dynamical laws: no dynamical theory can ever "predict" that we are Boltzmann brains because the second law depends on an additional layer of knowledge, the initial conditions, that remain pretty much outside physics (even today). Feynman ends the third part by ruling out a particular Maxwell's demon. So in the fourth part, he is led to clarify the difference between energy and useful energy.

He generalizes the insights about the increasing entropy by noticing that the laws of physics often do not have a direct relevance for the experience - one needed to analyze statistics instead of the microscopic laws themselves. We would say that some phenomena are emergent and many microscopic details become irrelevant along the way.

By knowing the laws, we don't understand "much" immediately. It takes a while and the understanding remains partial, anyway. What we see in Nature is an accidental consequence of a mixture of many elementary laws. So because many complex effects are involved (8:30), it is not surprising that Y(4140) has some complicated properties and seemingly accidental numbers.

Well, except for one 7.82 MeV level of Carbon-12 (9:00) that makes all the difference in the world, as Hoyle figured out. :-) So in the fifth part, Feynman shows that it was possible to predict that there was a 7.82 MeV level of the carbon nucleus. This very level allowed all the heavier elements to exist. I will discuss this point later.

In the fifth part, Feynman explains why it is important to invent emergent, approximate concepts in physics, such as "heat", that are not directly linked to simple objects appearing in the fundamental laws. This structure of concepts needed in science has many layers: it is hierarchical in character.

Needless to say, I think that the lecture is funny, perfect, deep, true, and nothing essential has happened to the irreversibility since that time.



Bonus: the 7.82 MeV level of the carbon nucleus

This observation is a cute example to test the anthropic ideas. Heavier elements are needed for life as we know it. And to create them, you apparently need the 7.82 MeV level of Carbon-12 because such a carbon nucleus created out of three alpha particles can live a little bit longer, so that it has a lot of time to be rearranged into the ordinary Carbon-12 ground state before it decays, and the creation of other elements becomes possible, too.

Now, the existence of this level is a nontrivial condition for life to exist. The energy of the level depends on many parameters, including the bare quark masses. (Of course, if it doesn't, then it means that the level follows from QCD with no dimensionless parameters - which means that mathematics of QCD has built-in "miracles allowing life": that would be a big argument against the anthropic reasoning.) Is this condition enough to constrain the vacua of string theory? How much does this condition and similar conditions constrain them?

I am sometimes afraid that the vacuum selection problem could indeed depend on objects as complicated as the existence of a required level of the Carbon-12 nucleus, a bound state of 12 nucleons or 36 quarks (plus many gluons and quark-antiquark pairs, among other stuff). It seems likely (but not certain) that there is no simple calculation that would link the levels of the carbon nucleus with those of the alpha particles in a general QCD-like theory.

However, I still think that this doesn't necessarily make the vacuum selection problem unsolvable. Imagine that there actually exist e.g. 100 similar constraints on the existence of different levels of nuclei, atoms, and organic molecules that may be needed for intelligent life of some kind. And the probability that a compactification passes all the tests and allows one of a relatively small number of possible "formats" of life is 10^{-500} or so.

I find it perfectly plausible. There can be just a few vacua that admit life. Or many of them. But whatever is the number of compactifications with life, we can still use all the data we have and all the parameters we have measured and try to find the most likely vacua by logical inference.

What I find important is that even if the constraints requiring the life to exist are real and relatively stringent, it doesn't mean that they're the only constraints or that they're the only hints that can lead us to the right answer.

BTW, if you liked the lecture, you may also watch The law of gravitation.

Perceiving randomness: egalitarian bias

After a long time, I am going to agree with a text written over at Cosmic Variance:

Perceiving randomness

Look at the following two pictures. Click to zoom in. We will call them the Ludolf map:



and the Coulomb map:



Which of them is random? Well, both of them look random, according to some distribution, so let me be more specific. Which one is more typical a representative of the probability distribution that has random, uniform, and independent coordinates {x,y} of each point over an interval?

Many people would say that the Coulomb map is more likely to be random than the Ludolf map. The Ludolf map seems way too clustered. In reality, it is the Ludolf map that is random, of course. Repetitions do occur. People usually suffer from the "egalitarian bias" and "psychological quotas".

People love to "balance things" much more than Nature does. People love to say that a sequence of random digits contains every possible value with approximately the same frequency. Nature loves to make the frequencies unbalanced. People love to make random maps uniform. Nature loves to include clusters and voids. Why do the people do this mistake? Well, it's probably because they secretly struggle for "perfection" and they believe that uniformity is similar to "fairness" and therefore "randomness".

Now a secret arrives. If you want to get to a higher level of abstraction and accuracy, none of the maps above was actually random. The Ludolf map was generated from pi. It's enough to say that the coordinates of the points were {314,159}, {265,358}, and 998 others. :-)

I called it the Ludolf map because in Czechia and Germany (and perhaps other countries), "pi" is referred to as Ludolf's number, after the Dutchman Ludolf van Ceulen who calculated 20 digits of "pi" in 1596. If you were a crazy genius (or if you saw my Mathematica notebook in advance), you could have said that the map was derived from "pi".

But if you only look at the statistical distributions and neglect many/most of the microscopic details, "pi" is indistinguishable from a sequence of random digits.

To be sure, the Coulomb map is not random, either. I started with the Ludolf map, gave electric charges to all the points, and moved all of them away from the three nearest neighbors, with some coefficient, in the direction of the Coulomb repulsive force. ;-) I repeated this step thrice or so.

Someone has conjectured that the schools are training the students so intensely that the new generations are likely to develop the opposite, anti-egalitarian bias. I kind of doubt it. The anti-Coulomb map, obtained by the same procedure (one step only) from the Ludolf map, but with the opposite sign, looks like this:



The clustering gets even worse if you repeat the procedure several times. I doubt that people will ever naturally think that such a map is "random" without correlations. Of course that they can be trained to avoid the bias or switch to the opposite bias. But the experience seems to say that people always give up their training and real insights and return to instincts and myths after some time.

The egalitarian bias is here with us to stay which is why the human society is likely to remain less efficient than Nature in many respects.

See also: random vibrating strings

Bonus: a random image



Click the image to zoom in.

The Fourier modes were chosen randomly, with a normal distribution, suppressed by a power law of the absolute value of the momentum. Yes, the picture is periodic in both directions; you can use it as a background image.

The exponent was chosen 1.5; the value 0.0 would give white noise (random independent pixels). The resulting three matrices (for R,G,B) were remapped to the intervals (0,1) via the Tanh function; the scaling coefficient inside Tanh was chosen to be 1.1.

You may draw your own pictures with a Mathematica notebook. I was surprised that the discrete Fourier transform was actually faster than all the other major steps in the creation of the picture.

BBC HARDtalk with Roger Penrose: before the Big Bang

We have already embedded and compared Hardtalks with Václav Klaus and Lee Smolin.



Here is one from 2006 with Roger Penrose, a very colorful and creative thinker, dealing with the pre-Big-Bang cosmology. See the full Real Video. In the remaining 10 minutes that are not available on YouTube, Penrose talks trash about quantum mechanics and defends the right of people to do pure science from the primitive journalist.

At some moment, they jump to artificial intelligence and consciousness of robots. Sackur can't distinguish "unconscious" objects from "man-made" things, so Penrose reminds him that we can make not only computers but children, too. ;-)

In my opinion, Mr Sackur confirms he is not fair. Klaus was asked where he took the "arrogance" to dispute the dangerous global warming theory promoted by those amazing "experts".

But when it comes to the Big Bang, suddenly it is "the most popular but far from unanimously" accepted a theory. Wow. So our robust state-of-the-art picture of the evolution of the Universe is just popular but it is "arrogant" to disagree with politicized pseudoscientific hacks who promote global warming fears - fears based on no non-trivial theory, no empirical evidence, and no high-quality scholars at all.

Sackur has tried to pump the global warming shit into Roger Penrose, too, convincing him that it matters more than the Universe. To be fair, he also spends 3 minutes trying to force Penrose to accept God. ;-) OK, let me stop complaining about Mr Sackur who is just an obnoxious BBC moron and let us return to the real cosmological issues.

A journey to ever more exotic corners of the Cosmos

One fact I find important here is that we are learning the story of the Universe essentially according to the scales of various types. In the case of the origin of the Universe, the age of the Universe is the crucial quantity.

The expansion of the Universe right now seems indisputable, and it seems obvious that we can extrapolate it billions year into the past when the Universe was smaller and denser.

The story almost certainly works up to the time when the Universe, starting from the conventional Big Bang, was 300,000 years old because this is when the microwave background - with features observed and correctly predicted by the theory - was created by "decoupling".

Our theory is arguably much more far-reaching and works up to the moment when the Universe was three minutes old and very dense: nucleosynthesis, the relevant part of the cosmic biography, is confirmed by the correct abundance of light elements we observe.

At this moment, after all those successes, it's sensible to trust quantum field theory coupled to general relativity. And because our effective quantum field theory, the Standard Model, was verified up to 100 GeV, we can say that we know the qualitative physics up to the ancient times when the Universe was a fraction of a second old.

Since that time, the Universe was expanding, the energy density was decreasing, but the total entropy had to be increasing because of the second law. The most obvious "minimal" hypothesis begins with a singularity. It is obvious that near this singularity, some additional laws of physics have to be added because every singularity in space is an ultraviolet effect that shows the incompleteness of your approximate (in this case even classical) theory.

But the next question must be what the new physics that governs the beginning is supposed to be.

Some people want to insert many cycles, proposing the cyclic models. I see zero theoretical or empirical evidence that this non-minimal model is superior. You know, if you have a minimal and simple model and a non-minimal one, you should expect the non-minimal model to give you better or more accurate predictions - or be consistent with a wider set of observations or insights. Otherwise the minimal model should be preferred.

The advocates of the cyclic or ekpyrotic models seem to think that they solve something by their non-minimal assumption but they have never explained what the something actually is. They surely don't remove singularities from the Universe. Because the entropy keeps on increasing, each cycle is longer than the previous one and the total geometric sequence can be summed, leading to a finite Universe, anyway.

Inflation

Instead, proper physics as I understand it postulates a robust modification of the expansion of the Universe at the very beginning, the cosmic inflation. It solves the horizon problem and various monopole and other "exotic" problems.

Inflation makes the Universe at the end of this stage pretty much flat, large, and independent of the detailed state at the beginning of inflation itself. I think that all these things are good features of the paradigm and when people get self-confident about the logic in the future, they may say that some of them are inevitable for a consistent theory.

The cosmic inflation is testable through detailed observations of the cosmic microwave background (and perhaps the gravitational waves) and it is arguably successfully tested. So I think that inflation is "just another successful step" in the one-by-one process, explained at the beginning, to reveal increasingly more exotic and inaccessible secrets of the Universe by increasingly penetrating observations and logic.

Dmitry, I don't really understand why Roger Penrose doesn't believe inflation either.

Low entropy at the beginning

Thank God, Penrose accepts that the second law of thermodynamics means that things get more and more organized if we move towards the beginning. At any rate, he seems to be puzzled by the low entropy. I think that this puzzled attitude is irrational. When the Universe was small and close to its most fundamental laws, it's clear that the entropy had to be "of order one".

On the contrary, it would be very puzzling if some initial, fundamental quantity - such as the entropy - was a huge constant very different from one to start with. In that case, we would be asking why it was this number and not another number? A new type of a hierarchy problem would be born. It is very good that the existing theories, especially inflation, allow us to explain very large numbers in the present Universe - like the number of photons - by an exponential formula.

Now, Penrose says that "no theory explains why the entropy was low to start with". Well, yes and no. No theory about the evolution of the Universe explains this - and it is obvious why it cannot. If a theory only describes things that occur after "t=0", it can't say anything about "t=0" or the time before it if there is any.

To say something about the initial state, we need to look at a theory about the initial conditions. So the correct question is whether e.g. the Hartle-Hawking state implies a low initial entropy, and I think it does. This wave function doesn't have too many competitors, so it's not surprising that questions about the very origin are ill-defined in virtually all theories we know.

Before the Big Bang

If you summarize what I said about the hypothetical evolution before the Big Bang, or about the initial conditions - which are two frameworks to answer the very same question at the edge of our current knowledge - it's clearly important that such a theory solves something and gives you a more sensible or accurate explanation of something that doesn't follow from the general vague assumption that the "Big Bang began with some unknown initial conditions" or that the "Big Bang began after some unknown pre-history". If you say something more specific, it should be the right thing and you should have some arguments that it is more right than other possible answers.

These are deep and difficult questions but I am not aware of arguments of this kind offered by Roger Penrose to support his opinions. So, using Occam's words, entities should not be multiplied unless it is necessary.

Eternal inflation

The canonical picture assuming the evolution of a broader Universe is the eternal inflation. Our Universe is born from an inflating seed in some parent Universe that had a similar origin. It's important to notice that this picture doesn't try to modify the most recent 13.7 billion years of our cosmic history textbook. It tries to change our idea about what happened before that.

A complete theory can make such an evolution - the growth of bubbles within each Universe - inevitable and preliminary results in string theory may indicate that it does so. However, one must still carefully distinguish what is established, what is motivated, which concepts are justified, and which are not.

If the seed of our Universe, starting with inflation or the Big Bang, is born out of a random fluctuation in a parent Universe, you may lose any observable consequences of the pre-evolution - as Stephen Hawking correctly emphasizes - and the correct physicist's attitude should be to cut off the whole pre-history.

Eternal inflation as a tiny Boltzmann egg

In this context, it is useful to mention that such a birth of the small Universe is a modern, modest, and realistic variation of the Boltzmann brain theory. Boltzmann was the guy who really discovered the idea that because the matter is made out of atoms, a finite piece of it carries a finite amount of information. One really needs some quantum mechanics to regulate the UV degrees of freedom but Boltzmann correctly predicted what quantum mechanics would later do with such things.

If the piece of matter carries finite information, all of its possible configurations may be born out of chaos, after some time. The only question is what the time is. Boltzmann was a pioneer of this statistical understanding of matter and we often underestimate how revolutionary these ideas used to be. So it is not surprising that he coined the concept of the Boltzmann brain, too.

But that doesn't mean that Boltzmann actually believed that whole organized brains are actually created out of chaos. He strictly believed Darwin's evolution. Well, he may have believed some Lamarck's ideas, too. But it is historically absurd to suggest that Boltzmann was serious proposing the "Boltzmann brain" paradigm as an alternative to evolution.

The creation of a seed of the Big Bang from a fluctuation in a pre-existing larger Universe was much closer to what Boltzmann had in mind. Believe me, he was able to calculate that it is possible to create microscopic objects as random "fluctuations" but the probability becomes nonsensically tiny if you want to create macroscopic organized objects.

OK, what about this idea, of a seed of our Universe as a fluctuation? Is it useful for something? Can't we simply truncate time at the moment of the statistical fluctuation, as Hawking dictates?

The a priori physicist's answer must clearly be Yes. If the Universe and its internal logic dramatically changes, in some very unlikely way, then it is the best description of a "new beginning" you can ever get in physics. You should forget the "time before that". This "time before that" and the "new time" cannot be identified, anyway.

If we want to use one time throughout some history, physics must be at least qualitatively continuous as a function of this time. If it is brutally and qualitatively discontinuous, the time coordinates in the two phases are really different degrees of freedom, in the very same sense in which the momentum and the winding number in one Universe are different.

Time is a theoretical construct

The ability to use the same "time" throughout a long history is a simplification, a result of assumptions that hold when the Universe is smooth, but assumptions that can break down if it is not. People often don't realize this fact so let me state it again: "time" is a theoretical concept. By connecting our present world with any other world via a continuous time, we are explaining certain things.

But that doesn't mean that this "theory" (of time) must be valid in an arbitrarily extreme context. In the extreme contexts, time may be - and probably is - an emergent concept.

It is always possible to drop this assumption about time that always exists and reformulate our predictions about our present and future observations without the assumption of a time in the far past. The time is always just an auxiliary concept, if you wish, and it becomes increasingly "abstract" or "unreal" if you move to increasingly exotic regions of spacetime.

When you get to the very beginning of the Big Bang expansion, you may be forced to drop the time as a concept. So the more general question you should be asking is what are the probabilities of different values of quantities when our Universe was very small. Can these probabilities be calculated from a pre-existing Universe?

Incidentally, Penrose agrees that time can "fail to exist". Except that his particular context in which time should disappear - the disappearance of massive particles - seems to be a wrong context to show this disappearance.

Looking at the DNA of the parent Universe

Now, if you need a very unlikely fluctuation, it is likely that "anything can happen". You may still argue that even among the unlikely events, some of them are more likely than others. And these likelier events could be derived from the pre-existing Universe. It is conceivable that our Universe was born from a piece of essentially empty space in the parent Universe. Fine.

I just happen to think that we will always be unlikely to derive any detailed information about the initial conditions from this sort of reasoning. If your probabilities about the current Universe depend on probabilities of different matter distributions in its parent, you are reducing a question about our current Universe to an equally difficult question about the parent Universe.

It just doesn't look like you are making a progress. Where's the beef? You are simply postponing the question, much like if you use God to explain the beauty of Nature, without asking who created the beautiful God. And every level of gods or parent Universes makes your theory more inaccessible and abstract, so unless you show me otherwise, it is sensible for me to expect that the situation is getting more hopeless, not more promising, as you are adding the layers.

And because I think that it is pure crap to link the probabilities of different options to the volume in a multiverse, there is probably no way to convince me that this construction of new layers in a Universe is scientifically valuable.

Also, if you try to imagine the initial configurations of matter in our Universe that were likely to emerge from a different one, I think that you won't be able to derive any "microscopic details" about the seed of our Cosmos. In the most optimistic case, you will be able to say that it was small and its scalar fields were pretty closed to to one of "selected" stationary points in the configuration space (landscape).

That would be great and it could be enough to solve the vacuum selection problem. But the whole long pre-history in the parent Universe would almost certainly be useless for such a hypothetical victory. In this sense, we should still say that our Universe began with the ordinary Big Bang.

New theories must bring new results

The text above defines what kinds of questions, answers, and explanations can a priori exist. You may view them as tautologies because I am not really assuming anything that should be controversial. On the other hand, if someone wants to say something about the initial conditions for our Big Bang, he must actually have some results that make sense - some predictions or some derivations that are made inevitable by other established pieces of theory.

I am afraid that many people in this area, including some very well-known people, are just bullshitting around. They have no results, they have no logic that puts things together, they have no new mathematical objects that can be shown to be relevant for quantum cosmology: they are just trying to be interesting by taking sides. And that's not interesting for me.

Via Dmitry.

Jan Fischer: the new Czech bureaucratic government

The Czech politicians have agreed on the name of the new interim prime minister: it is Jan Fischer (*1951), the current "apolitical" boss of the Czech Statistical Office, appointed by ex-PM Špidla and (officially) President Klaus in 2003.

Both of his parents were mathematicians.

Well, your humble correspondent is surely not thrilled by this temporary solution - the "summer government" (a term hated by President Klaus) will reign from May to October when the early elections should take place.

While this solution was agreed upon by the four non-communist parties in the Parliament, Fischer was a member of the Czechoslovak Communist Party between 1980 and 1989 so it is really the only party that was left out that is probably going to secretly celebrate. ;-)

The communist membership was a typical approach of the career-driven opportunists in the 1980s, most of whom left the communist party during the Velvet Revolution. As we were taught at the basic school (before the fall of communism!) by our class's teacher, a communist can't be both ethical and intelligent. I may have forgotten the third adjective.

Moreover, although I don't know much about this particular guy, I feel that most of these people were not members of the communist party just for the sake of their careers. A communist way of thinking - e.g. some kind of obsession with regulation of everything from above - seems to be deeply rooted in the minds of most of them.

I don't know what is the causal relationship here. It might be that they have been infected by the disease while they were members; it might be that they joined the party because they did believe it, in some sense. Or some mixture of both influences could be relevant. At the same moment, I have to admit that the average communist party members were more interested in politics and more skillful than average citizens.

While I feel that such picks partially return our politics before 1989 - to the era of faceless politicians substituted from above who only had to be convenient for other faceless politicians - I guess that the politically correct media and similar circles may be happy about the choice.

The Czech Republic has already had a bureaucratic, "apolitical" government back in the early 1998, after the "Sarajevo assassination" of former prime minister Klaus. The prime minister at the time, Josef Tošovský, who was close to the Prague Castle led by Havel, was not a guy who would create deep emotions but he was just fine and I even wanted him to become the IMF boss or what was that when he was a candidate.

Despite his proximity to anti-communist Havel, Tošovský has also been a member of the communist party, between 1976 and 1989, and he was even accused of collaboration with the communist state secret agency. But he seemed (and seems) to be a pro-market guy.

Fischer has no future political ambitions and his main stated goal is to smoothly complete the so far successful Czech EU presidency. However, many politicians want the current government to stay up to the end of the presidency.

Update: The Castle and the two major parties seem to be happy with the new prime minister (who is supposed to fill the whole government with non-partisans) - so the agreement could be a step towards the grand coalition that is kind of favored by Václav Klaus. The president is happy with the new prime minister, too (despite his disapproval of apolitical governments in the past).

Because the new government is getting this "grand coalition" flavor, the smaller parties - Christian Democrats and Greens - are beginning to oppose the deal. But of course, the social democratic and civic democratic (grand coalition) votes would be more than enough to make this government work.

Guantanamo

One more comment. Most European countries, including Czechia, plan to accept no detainees from Guantanamo.

When reality supersedes meaningless idealistic talk, the detainees are again what they have always been: dangerous thugs who were getting pretty much what virtually all of them deserved. It's not easy and cheap to deal with this material, especially if you risk bad publicity whenever you have to treat them stringently.

I think Europe should often naturally help America - and even its charming president - but this seems to be a purely internal issue of America. These are people who were arrested according to the U.S. rules, to serve the U.S. interests, and now they are being semi-liberated according to other U.S. rules, moods, and policies. The other countries know nearly nothing about these individuals and they're not ready. The help could look like a nice gesture but the consequences would be that the treatment would be much less well-informed and focused than what America is able to do.

Barack Obama in Prague

Sunday - the full anti-nuclear speech in Prague:



See also excerpts from the Klaus-Obama military parade, 28 seconds of the bilateral meeting, a minute from the Havel-Obama meeting, EU-US Prague family photo preparations (1 minute), and some more Obama video background from Sunday in Prague.

Back to Saturday, before he arrived. Sorry for the lack of a uniform arrow of time in this text. ;-)

Obama gave a nice present to the British queen, an iPod. Next time, they can play Bump Bump together. Will Klaus receive one, too? Update: Klaus received a bust of Obama's predecessor whose name is not known but I guess it wasn't George W. Bush. The Obamas have received books about the Prague Castle, glass, while Michelle gave Livia a vase.

Everyone noticed that Michelle changed her dress every hour ;-) but almost no one knows that Klaus and Obama conspired to use blue and red ties on Saturday, and they switched them to red and blue on Sunday, in this order.

Global warming - Sunday update:

Klaus said that Obama told him that as he (Obama) speaks to his advisors and other climate change advocates, they seem to have no sense for the economic reality. That sounded like a music from the heavens to Klaus's ears, Klaus said. ;-) The two presidents obviously liked each other.

At the end, it was Havel who made the picture less enthusiastic when he warned Obama against excessive expectations in Obama himself that may transform into a hatred if things go wrong. Havel described Obama as an ordinary citizen who cares about the Earth.

In Strasbourg, Obama invented the Austrian language. If Bush had done the same thing, the media would be full of hateful comments about his stupidity. But no one (except for the Czech media!) cares that Obama has no clue that the Austrians speak German. Things are OK - Barack Obama kissed Angela Merkel's husband, after all. :-)

Today in the afternoon, the second black U.S. president left the aggressive communist mobs in Strasbourg, France, joined his Cadillac One (his second car) that has been here since Thursday, and arrived to Prague, the new capital of peace and capitalism.



BHO landed around 6:32 pm - see a one-minute video, a three-minute video, and 120 pictures with the first Klaus-Obama warm scenes - and went to Prague Hilton.

To protect his life, sharpshooters will have to erase, off the surface of Earth, all citizens of Prague who open their windows by mistake. ;-) Let's check whether they haven't forgotten about the safety of Air Force One: Czech journalists managed to wiretap the Air Force One pilots.

He and the first lady plan to romantically eat some Czech cuisine - perhaps the Candle Sauce or a Duck with Red Cabbage and Potato Loafs - in The Golden Well (pics), a luxurious place under the Prague Castle. An average dinner costs USD 100 here, if you want to join (later). Sunday update: they stayed in Hilton overnight.

So Obama will have neither a dinner with Klaus at the Castle, nor some beer with PM Topolánek, despite their invitations. Just another boring dinner with Michelle - Summer time in Prague. Hillary will have a dinner with Havel.

AHA, Czech newspapers, emphasize that the D Day has arrived: Bimbo Obama is flying to Prague. They explain that BHO got the nickname as a kid, because of his detached ears.



Tomorrow in the morning, he will meet President Klaus and his wife (and maybe caretaker PM Topolánek). Klaus should teach Obama some rudimentary economics and climate science. He may also give a copy of "Blue Planet in Green Shackles" to Obama, so that BHO doesn't have to exclusively rely on his green advising nuts. Later in the day, Obama will meet ex-president Havel, too.

Around 10 a.m., BHO, equipped with his nuclear suitcase and a Barrackberry, will speak on the Hradčany Square - see the picture above and a video with some preparations - about nuclear proliferation (here is the URL with live pictures showing Obama's dreams about the world without nuclear arms).

Update: transcript is here. See the full video (pure English) or the same with a page around it and a 15-second ad or video (3 parts) with Czech translation. The speech seemed extremely good. He managed to incorporate the (failed) fresh North Korean long-range missile attempt into the text. Aside from a general strategy to regulate everything linked to nuclear weapons, he talked about the good-spirited Czechs he knows from Chicago (a city with a strong Czech community), the memories of 1918 when the U.S. helped to create Czechoslovakia, The Velvet Revolution (that he pronounced in fair Czech), and so on. Unfortunately, he also mentioned global warming, suggesting that Klaus's previous 30-minute class was unsuccessful. ;-)

Meanwhile, Michelle Obama impressed her guides and public, and was very happy in Prague, the Castle, and the Jewish Quarter (pics). She plans to return.

Let's hope that in his attempt to resemble Reagan, Obama won't ask Klaus to "tear down this wall" of the Prague Castle. ;-) Afterwards, he will prepare for the EU-U.S. summit in the Congress Palace (known as the Palace of Culture during late socialism).

I don't have immediate plans to meet him. But you may listen to a funny out-of-tune "anthem" to welcome Obama: typical music from the Czech pubs. The translation:

Obama will arrive here.
The whole Prague is upside down.
He will come from the States,
he who is the Big Cheese of all Big Cheeses.

It will support the Union,
the crisis can't demolish it, after all,
we will also welcome Hillary,
she will spend her dollary [dollars].

So eat the food,
you are skinny.
You'll have a dumpling
and you'll be ours.

So welcome, Barack,
welcome to us, welcome to us,
to our European barák [house].

A namesake of mine has created a 3D model of Obama, too. And one of the three cute newborn leopards in the Dvůr Králové Zoo was named Barack. So everything is ready.

To restore some arrow of time in this article, check Obama's jogging back to Air Force One that flies to Turkey.

Saturday - Summers

Meanwhile, the U.S. media and blogs are playing a hysterical, populist game against Larry Summers who has recently (in one year) received USD 5.2 million in compensations from D.E.Shaw plus $2.7 million speaking fees. Would they ever consider the possibility that unlike Al Gore, he deserved it?

RSS MSU: 0.06 °C month-on-month cooling

If you remember a discussion that was posted one month ago, RSS MSU (Remote Sensing Systems, advanced Microwave Sounding Unit) was one of the teams that reported that February 2009 was (0.09 °C) cooler than January 2009, in terms of the global temperature anomaly.



It turns out that March 2009 was even cooler, matching the anomaly from December 2008:

2008/12: 0.172 °C
2009/01: 0.322 °C
2009/02: 0.230 °C
2009/03: 0.172 °C

Two months are enough for 0.15 °C of cooling. Let us see whether our climate realist friends at UAH MSU will continue in their warming trend - and in their divergence away from RSS MSU. :-)

Update: no. As expected, UAH MSU reported cooling, too. But guess how much: 0.14 °C per month!

The mid troposphere cooled by 0.09 °C in one month (RSS). In this layer, the anomaly of the Arctic dropped (cooled) by 1.5 °C in one month!

The cooling appears despite the fact that the recent La Nina conditions are essentially over. During the most recent week, they have been replaced by ENSO-neutral conditions.

In the U.S., 358 low temperature records and 409 snowfall records were broken during the most recent week. New blizzards are expected.



Meanwhile, the Sun remains officially spotless for the 26th day in a row, delaying a sharp beginning of the 24th solar cycle. The Dalton minimum may be repeated, indeed.

The sunspot number behaves much like the Dow Jones index. Just when you think that you have hit the bottom, it goes even lower. ;-)

By the way, the global sea ice area anomaly is actually slightly positive right now. It means that the excess of ice on the Southern Hemisphere, relatively to a typical early April since the late 1970s, exceeds the deficit of ice on the Nothern Hemisphere.

Of course, such facts - and no other facts - can't prevent the champions of climate hysteria from writing about a catastrophically melting ice. The threats and stakes are infinite, after all, and (their) rational thinking breaks down whenever infinities are encountered.

Keep on reading this blog. :-)

Bonus: parameters of solar cycles

You may download this Mathematica notebook or its PDF preview.

It downloads the sun spot numbers from January 1749 to March 2009 (as reformatted by JunkScience.com - very convenient); it divides them to 23 pretty much complete cycles (the zeroth cycle at the beginning is incomplete and the 24th cycle is barely starting now) using a Lumo formula; it calculates the length, average strength, and a Lumo asymmetry of the cycles; and it shows the correlations between these three quantities for a given cycle (and the previous cycle).

Not too surprisingly, the two strongest correlations tell you that a long previous cycle means a weak and delayed (with a positive asymmetry, i.e. the maximum of sun spots is closer to the end) new cycle.

God and Boltzmann eggs: dogmas and infinite priors

At the end, I added some comments about the general proof of the second law of thermodynamics in quantum mechanics.



Apologies to readers who are believers but I found it funny and deep.

The discussions about the Boltzmann eggs have reminded me of the psychological power of dogmas, fundamentalism, and circular reasoning once again.

Imagine the following old-fashioned set of hypotheses:

1. the world was created exactly as described in the Bible
2. for example, the electromagnetic field was created after the Earth
3. life was created within seven days
4. and so on...

At some level, that's an internally self-consistent framework. That's why it could have been believed by decent and relatively smart people for long centuries. This framework can be reinforced in many ways:

1. the infinite power of God is independently confirmed by many books of the Bible
2. that's why He is really "infinitely^66" powerful, not just infinitely powerful
3. because God is infinitely great, no competing hypothesis can ever have a chance and no experiment can be important enough to change the conclusions above; after all, thou shall only have one God
4. and so on...

The Inquisition vs heretics

You can see that the framework is self-consistent and powerful, indeed. ;-) But some heretics have asked whether the framework was right. Well, if you use the internal logic of this framework, it is certainly right: any doubt about it is a heresy.

However, if you are open-minded at the beginning, if you formulate, read, or hear alternative explanations, and if you compare them with the creationist picture of the world, your conclusions may differ and will differ. The evidence will support a completely different theory about the origin of species - one that was written down by Charles Darwin - and a different theory about the origin of light that has been similar to the present light at least for 13.7 billion years.

This method to derive similar conclusions, some of which may turn out to be heretical, is called science. It requires the people to be open-minded at the beginning, to admit that any assumption can a priori be qualitatively wrong and any alternative assumption can a priori be qualitatively correct. And it requires the people to evaluate the evidence that gives us hints which hypotheses are more likely and which hypotheses are less likely.

Statistically antireligious bigots

Many people oppose religion because they think it is not scientific. But if you look what these people actually believe, you will find out that their reasons to consider religion unscientific are irrational - and that their own beliefs are equally unscientific as the beliefs in the religious example above. In fact, their beliefs are structurally isomorphic.



Consider the following set of postulates:

1. there are infinitely many possible cosmological models
2. many of them describe the past of our Universe as one that contains an infinite (or nearly infinite) spacetime volume with a nonzero density of matter
3. in these infinite (or almost infinite) regions, all localized configurations of matter (microstates) such as those of eggs appear (nearly) infinitely many times
4. on the other hand, the evolution from a tiny, low-entropy Universe appears only a few times
5. it is thus infinitely (or almost infinitely) more likely that our life was born as a statistical fluctuation, from a Boltzmann egg, or our brain was directly created as a Boltzmann brain
6. because of this (nearly) infinite discrepancy between the priors, no finite number of arguments or experiments can change the conclusion that we are just a statistical fluctuation that evolved completely randomly
7. and so on...

Again, this set of ideas is internally self-consistent, as long as you don't care about too many observations about the reality such as the existence of irreversible phenomena, aging, evolution, natural selection, friction, memory, heat, or any other effect or thing in the physical Universe. ;-)

This set of ideas is so powerful that any hypothesis and any theory that includes the statement that the entropy in the past was low is excluded. It is permanently excluded, at least in the minds of the champions of this reasoning. Science as we know it is forever guaranteed to be in
compatible with this "statistical argument". Science as we know it sucks, these people think. The paradox is inevitable.

The blasphemy of thermodynamics

Now, is that right? You may guess what the right answer is. Of course, this set of ideas is not right. The people who believe it - such as Sean Carroll - are irrational bigots in the very same sense as Pat Robertson. The main difference is that Pat Robertson has an actual anti-aging protein shake (because he can leg-press 2,000 pounds) while Sean Carroll only offers a cartoon of an egg that defies aging. What is the mistake that the people like Sean Carroll are doing? The mistake is that they are simply unwilling to admit that their assumptions may be fundamentally wrong.

By assigning their assumptions with prior probabilities that are pretty much infinitely greater than the prior probabilities of all competing hypotheses, these people confine themselves into a dogmatic mode of reasoning. It is very clear that if you set the prior probabilities of all competing hypotheses to zero - or to exp(-10^{120}) which is effectively the same thing in any conceivable context - logical inference will never be able to "undo" this bad prior. Why?

Hypotheses must be given a chance

Well, Bayes' theorem leads you to use the evidence E and to adjust the prior probability of a hypothesis, P(H), to a new one, P(H|E), according to the formula

P(H|E) = P(H) P(E|H) / P(E)

You can see that if P(H) is zero, P(H|E) is also guaranteed to be zero regardless of the probabilities that the evidence occurs: P(E|H) is the probability that E occurs, as predicted by the hypothesis H, while P(E) is the probability that the evidence E emerges according to all competing hypotheses, weighted by their priors (which cannot be zero, otherwise all hypotheses would be incompatible with E).

In other words, if you assume that a hypothesis - such as a Godless origin of species or a low-entropy beginning of the Universe - is a priori impossible, no finite amount of observations or arguments will be able to change your mind. If that's the case, you are a closed-minded bigot. If the prior probability of a hypothesis is exp(-10^{120}), it is not quite zero but the practical result will be identical: no conceivable set of arguments or experiments may ever convince you that you are wrong.

In a rational, scientific approach, every qualitatively different hypothesis about the world must be given a chance to be supported by evidence and every hypothesis about the world must be allowed to fail. In science, there is simply no room for a priori judgements such as the "infinite God" or the "infinite dominance of high-entropy states in the past".

Although these systems of ideas involve (nearly) infinite objects that make certain statements (almost) infinitely certain, within the same system to calculate the probabilities, that doesn't mean that these statements are certain. This implication doesn't exist because of a simple reason, namely that these systems of ideas may be fundamentally wrong - which makes all their internal "infinite" statements worthless. And indeed, they are fundamentally wrong as the most basic scientific tests immediately show.

A reader wanted me to prove that by collecting additional evidence, we can fix the wrong priors for the low-entropy initial state and find out that the probability of a low-entropy initial state of the Universe is actually high. However, if the prior probability for a low-entropy initial state is zero or exp(-10^{120}), such a task is impossible. It is impossible for the very same reason why you can never defeat God in His own disciplines. :-)

If you accept the assumption that God and all the statements about Him are infinitely greater than anything you can ever do and say, it is simply impossible to show that evolutionary biology is superior relatively to creationism. If you accept the infinite truth of Genesis as your zeroth approximation about reality, an (almost) infinite struggle against the wind mills is the only possible fate awaiting the heretics. ;-)

In the very same sense, if you accept the assumption that the high-entropy initial states are exp(10^{120}) times more likely than the low-entropy initial states, all the people who disagree with you, the heretics who believe thermodynamics up to its second law or even beyond ;-), are obliged to find an effectively infinite miracle that beats your effectively infinitely powerful argument.

Except that you're wrong in the very same sense as your Christian colleagues. The nearly infinite factors that you like to talk about do not measure the actual validity of your framework. They only determine how much blinded you are in your defense of your wrong dogmas.

Past and future: symmetries

The hypothesis that the Universe in the distant past should have a higher entropy than the current entropy is simply fundamentally wrong. It contradicts the second law of thermodynamics which holds according to all observations. It contradicts the proper theoretical derivations that are relevant for statistical physics and thermodynamics. Because the entropy increases with time, the entropy in the distant past had to be lower than today, not higher than today. Any retrodiction about the past that ends up with a qualitatively different conclusion is wrong - in the scientific sense.

What's exactly wrong with this framework? Some time ago, I wrote 7 postulates of this "high-entropy" ideology. They said that one can imagine models with infinite spacetime volumes - sure, one can do so. One can imagine that certain events are repeated infinitely many times - sure, you can think about such models. Another postulate number 4 said that the Big Bang evolution only occurs a few times. That's not really true because the evolution from the Big Bang (and Darwin's evolution) can also be repeated infinitely many times across your big multiverse.

So the point 4 is really incorrect. The evolution of mammals from more primitive organisms will still occur much more often than a spontaneous emergence of a mammal from a chaotic piece of matter.

But the most incorrect postulate is the postulate number 5. This postulate claimed that the infinite spacetime volume in some cosmological models implied that life has emerged as a statistical fluctuation. That's simply wrong. There exists no logical procedure that would allow one to derive such a conclusion simply because there exists no universal law that probabilities are proportional to the number of possibilities.

Even if you can write down infinitely many possibilities describing our Universe in a certain way, it doesn't mean that one of these possibilities has to be right. These possibilities can still be wrong - and a completely different possibility that you didn't include into your ensemble, even if it is just one possibility, can be correct. The number of microstates is not the same thing as the probability. These are completely different concepts.

I used to think that people must have already understood what was wrong with Zeno's paradoxes. For example, the trajectory of Achilles trying to catch up with the tortoise can be divided to infinitely many pieces. But that doesn't mean that he can't ever overtake the animal, does it? ;-) Sums of infinitely many numbers may converge!

The idea that all the microstates are equally likely is valid in certain contexts but one must be very careful what the contexts are. The conclusion is valid for the configurations of matter after a long enough time when "thermalization" could have occurred. If a closed, non-integrable system with many degrees of freedom evolves randomly, it eventually ends up in a "random" or "generic" point of its phase space or Hilbert space (more precisely, its subspace where the conservation laws are respected).

But if you omit the assumption about the thermalization time, the statement that all microstates are equally likely is not correct. In general, it is wrong. And if you study the state of the Universe in the distant past, it is fundamentally wrong. The truth is diametrically different. While the assumption about "generic" states is getting increasingly valid in the future, it is becoming increasing invalid if you go into the past, essentially for the same reason. A few basic observations - observations of an increasing entropy - are enough to show that the idea that the entropy decreases with time is incorrect.

If you insist that people should give you (almost) "infinite arguments" or "miracles" to defeat your assumption that all the microstates in the past are equally likely, the only thing you are showing is that your bigotry and your unwillingness to objectively look at the evidence is (almost) infinitely large.

No cosmological model that includes the well-established laws of local physics can ever predict that the eggs unbreak as often as they break. The reason is that the breaking of eggs is a local phenomenon. It means that the breaking of eggs only depends on the local behavior of your model of physics. It follows that it can't possibly be influenced by any changes of the cosmological features of your model of the Universe.

The idea that the entropy should increase both into the future as well into the past implies that the entropy should be minimized at the present. But the present is not a scientific term. The present means something else than what it meant when you were reading the previous sentence. No objective law of physics can assign the "present" with a privileged role. The idea that the present is special brutally contradicts the time-translational symmetry of the laws of Nature. The latter symmetry (linked to the energy conservation by Noether's theorem) has been verified with a huge accuracy - unlike the time-reversal symmetry of the macroscopic phenomena that has been (easily and repeatedly) ruled out.

OK: which symmetry wins?

Again, there are two possible symmetries of the macroscopic, effective laws of physics that you may consider and appreciate in this context. One of them is the time-translational symmetry and the other one is the time-reversal symmetry. However, if you have ever looked outside the window of your office or anywhere in the real world, you must know that the macroscopic phenomena look pretty much identical if you shift them in time, but they look dramatically different if you revert them in time.

For example, you can watch a movie after it was shot - and it looks OK. On the other hand, if you watch a time-reverted movie, you get something like this:



Some people find this video as sensible as the original one - yet they still have the guts to call me "reactionary". ;-)

Do you know why the people in the normal world look in front of them, in the direction of their motion, and not in the opposite direction? It may sound surprising for Sean Carroll but it's because the eyes exist in order to help the people to plan for the future. They can't plan the past because the past is already gone. ;-)

Also, to do their present job, the eyes collect the information from the past light cone. Again, they can't collect any information from the future because it is not yet decided i.e. not yet available at the present. :-) Because of quantum mechanics, the future developments will depend on random, probabilistic outcomes of events that can't be known now (see e.g. the free will theorem that makes this point really sharp). That differs from the past which is already settled. But that's not just quantum mechanics: in any realistic sense, the future is "unknown" even in classical physics.

The correct arrow of time is also crucial for the relatively low concentration of traffic accidents: the video above wouldn't work in this way because the pedestrians or drivers walking or driving backwards would be colliding all the time.

There exists no corner of the Universe - and no other Universe - where the people are making plans for the past. The difference between the past and the future is huge and logical in character. An arrow of time must always exist in every Universe whose basic architecture resembles ours. And by choosing a proper terminology, the past is what cannot be changed while the future is what you may plan for. This logical arrow of time inevitably agrees with the thermodynamic arrow of time and the direction of decoherence.

So the observational data speak in a clear language. The macroscopic features of the phenomena in the real world are compatible with the time-translational symmetry but they are completely incompatible with the time-reversal symmetry at the macroscopic scale. Theories that effectively describe macroscopic phenomena therefore cannot be time-reversal symmetric. And indeed, they are not. Friction, diffusion, viscosity, aging, decoherence, and other phenomena introduce an arrow of time into the realm of macroscopic phenomena.

Not only the arrow of time for these phenomena is compatible with the (approximately, but almost exactly) time-reversal-symmetric (or exactly CPT-invariant) underlying microscopic processes. In fact, the coefficients of the time-reversal-asymmetric phenomena - such as the coefficients of friction or the speed of decoherence - may be quantitatively calculated from the first principles, too. Boltzmann's H-theorem was the first pioneering calculation showing how to do so. This calculation and its followups agree with all the observations while the dramatically different philosophical frameworks don't agree with any observations.

In science, the previous sentence makes a difference. You may find some features of Boltzmann's derivations "ugly" but they are physically deep, true, quantitatively accurate (in the thermodynamic limit), and robust (i.e. invariant under detailed modifications of the assumptions).

You know, the very concept of entropy is slightly ill-defined because the clustering of states into macroscopically indistinguishable ensembles depends on many choices. Correspondingly, the laws (e.g. the second law) can sometimes be violated for a little while, with a small probability. Nevertheless, the impact of this clustering of microstates on macroscopic physics is very real and pretty much universal. This impact is studied by a science called thermodynamics and even children can feel that something is hot and something else is cool!

Anthropic brainwashing

The fallacy of the infinite priors - i.e. the people's inability to realize that they are blinded by some dogmas that can be wrong (and that often are wrong) appears at many places in the world. The champions of the anthropic reasoning suffer from similar fallacies all the time, too. Their defining assumption is the assumption of "typicality". It says that all the different Universes should be equally likely.

Now, some of them agree that it is an arbitrary "egalitarian" assumption that has no reason to hold exactly. However, if they're anthropic believers, they will always tell you that the assumption about the equal probabilities of all vacua must be the correct zeroth approximation. All other effects must be small corrections.

If you ask them about the evidence supporting their assumption, you won't get any. The reason is simple: there is no evidence. The assumption is nothing else than a dogma. Those people only differ in their degree of fanaticism i.e. in their tolerance for "corrections" that are allowed to modify their egalitarian priors. But none of the anthropic people is able to understand that their assumption may be qualitatively, fundamentally wrong.

And be sure that it is fundamentally wrong. The number of all vacua in quantum gravity is really infinite - it's enough to consider the AdS5 x S5 vacua to see why - and there is no uniform probability distribution on an infinite countable set. The weight of the "numerous" classes of vacua that make the total number so infinite must be dramatically reduced in order for the total probability to converge. It is plausible and, in fact, extremely likely that the probability of the excessively large classes is reduced so that even these whole classes are less likely than the small classes.

This answer is suggested e.g. by the analogies with thermodynamics above. Not only the high-entropy microstates are less likely than the low-entropy microstates. But even the sum of the probabilities of the huge number of high-entropy microstates - i.e. the probability of a high-entropy macrostate in the past - is smaller than the probability of a low-entropy macrostate in the past. That's how the world works, whether you like it or not. The probabilistic distribution on the space of vacua in string theory, assuming that there is a distribution that waits to be clarified by science, is likely to obey the same rule. It seems necessary for the total probability to converge.

Moral of the story

If someone tries to throw away an alternative argument by claiming that the a priori probability of his argument is (almost) infinitely higher, you should always be careful. Is there some evidence that it is (almost) infinitely higher? And if such claimed evidence is based on the claim that there are many possibilities that are equally likely, is there actually some evidence that the numerous possibilities are equally likely?

If Lee Smolin tells you that you may ignore string theory because there are roughly 12 competing theories (a high number!) with various kinds of swimming octopi that are equally likely as string theory, does he actually have some evidence that the crackpot fantasies are equally likely as string theory?

To make the inconsistency and irrationality of his whining more obvious, Smolin says that the "alternative" theories should be supported because there are roughly 12 of them which is (impressively) many while string theory should be suppressed because it has 12 or so scenarios which is (too) many. I still can't believe that some people may be so dumb that they are ready to buy this incoherent propaganda as a package.

The number of hypotheses and their probabilities are completely different animals. Unless there exists some evidence, these quantities ("N" and "Prob") cannot be assumed to be negatively correlated and they cannot be assumed to be positively correlated.

In the thermodynamic and anthropic cases, there is no evidence. In fact, there exists counter-evidence suggesting that these statements are wrong. In the thermodynamic case and in the Smolin case, this counter-evidence is overwhelming. But there are many other situations where both the evidence and the counter-evidence is absent. The people who try to strengthen their propositions by talking about (nearly) infinite numbers often have no rational justification for their statements and the (nearly) infinite quantities only determine their fanaticism, i.e. their willingness to replace rational arguments by shrill irrational arguments.

The (nearly) infinite catastrophes hypothetically caused by global warming are just another example. There exists no rational evidence that global warming will cause any problems - and this missing rational evidence for finite problems cannot be replaced by irrational evidence that global warming will cause infinite problems. ;-) But you can surely find many other examples outside the field of global warming pseudoscience, too.

And that's the memo.

Off-topic: Fermi (GLAST) essentially kills all Lorentz-breaking theories (which includes all existing alternatives to string theory): the paper has appeared in the regular Science Magazine.

Bonus: quantum mechanical H-theorem

I urge all the interested readers to look at this proof of the increasing entropy using the tools of quantum mechanics. This quantum-mechanical "upgrade" of Boltzmann's own proof is very transparent. (I also recommend you a similar cute, solid, quantum-field-theory-friendly proof by Steven Weinberg, Quantum Field Theory vol. 1, pages 150-151.)

The only assumption that is being made is that one can choose a basis of the Hilbert space in which the off-diagonal elements quickly decohere, i.e. can be set to zero after each step "dt". Of course, if this assumption were not adopted, the entropy defined by the sum of "-p_i ln(p_i)" would have to be interpreted in terms of eigenvalues "p_i" of the density matrix and the sum wouldn't change at all (because of unitarity).

If we do accept the assumption/approximation, the evolution of the nonzero, diagonal entries in the density matrix, i.e. the probabilities, follows T-symmetric microscopic laws that can be replaced by Fermi's golden rule, by another assumption that the "p_i" are probabilities that combine a couple of practically indistinguishable states (the usual assumptions of Fermi's golden rule), and one gets a very explicit, quantitative formula for the manifestly positive increase of entropy of any system with many degrees of freedom (i.e. any system where the entropy makes sense).

While the proof is a moral explanation of the origin of the entropy increase, the most accurate (and highest) formula for the entropy growth is actually obtained if we distinguish all microstates (a basis of the Hilbert space) and "p_i" are the individual diagonal entries of the density matrix - even though the assumptions of Fermi's golden rule don't strictly hold with this choice.

In this quantum mechanical proof, it is decoherence that kills the information and spreads the probabilities over many microstates. But any kind of rounding, coarse graining etc. will have the same qualitative effect. The entropy defined by the formula may sometimes decrease for a while but only by steps (and for time intervals) that are small enough for one of the assumptions above to become invalid.

All this stuff is very serious, very well understood, very universal, very quantitative, and very accurate. The origin of the entropy increase is very local and very microscopic. Attempts to create the illusion that the arrow of time is not understood even at a vague level - and that it should be getting connected with some mysterious or global ideas about religion or cosmology - are attempts to propagate pure ignorance and stupidity.

Myths believed by some AGW skeptics

Roy Spencer finally wrote a text that I wanted to write for quite some time:

In defense of the greenhouse effect

We frequently hear arguments from the fellow skeptics that the greenhouse effect has to be impossible, exactly zero, that it contradicts some basic laws of mechanics, thermodynamics, and so on.

Well, these thoughts lead to the correct practical conclusions: it is absurd to spend trillions to "fight climate change".

But from a scientific viewpoint, all these statements are as ludicrous as the statements of the alarmists that the ongoing "climate change" threatens life on the Earth. Every effect that cannot be proved to be zero - by symmetries and closely related principles - is guaranteed to be nonzero. That's why there are so many other effects, too. The only question are the coefficients, i.e. the strength of all these effects.

As Roy Spencer explains, the greenhouse effect is technically different from the effect used in the greenhouse with vegetables. The greenhouse effect is about the infrared absorption while the greenhouse mechanically prevents heat convection. But both of them reduce the ability of the system to cool down, which means that the equilibrium temperature increases. The only question is how much.

The bare value (neglecting rain, effects on other parts of the atmosphere etc.) can be calculated for the CO2 greenhouse effect from well-known laws of physics: it gives 1.2 °C per CO2 doubling from 280 ppm (year 1800) to 560 ppm (year 2109, see below). The feedbacks may amplify or reduce this value and they are influenced by lots of unknown complex atmospheric effects as well as by biases, prejudices, and black magic introduced by the researchers.

Chris Colose, an AGW advocate, attempted to criticize Richard Lindzen's demonstration that positive feedbacks cannot dominate. Well, the best thing he could do was to use some alternative graphs to argue that the current models underestimate the negative feedbacks by a factor of 2-3 rather than 5-7. This factor of 2-3 corresponds to no feedbacks. Well, a multiplicative discrepancy by a factor of 2-3 is still a pretty bad rating for the models, isn't it?

And let me tell you something else, too. So far, I can't reproduce some of Richard Lindzen's numbers. For example, Richard says that we have already realized 70% of the warming resulting from the CO2 doubling. I can imagine that a more complete calculation (involving overlapping spectral lines with other gases?) gives this result. But the simple logarithmic calculation I can do gives me a different result:

Log[385/280] / Log[560/280] = 0.46

In other words, we have made about 46% of the warming expected from doubling so far. It's almost 50%. So because it has led to something like 0.6 °C so far, assuming that we generously attribute the whole 20th century change of the global mean temperature to the CO2 enhanced greenhouse effect, we may expect that the rest of the doubling will lead to additional an 0.6 °C of warming: the total sensitivity is thus 1.2 °C per CO2 doubling, just like expected from the bare greenhouse effect. There are other, independent calculations leading to a similar value, including the calculation by Stephen Schwartz and pretty good reconstructions by Svensmark et al. who describe the 20th century temperature in terms of galactic cosmic rays, ENSO phenomena, volcanos, and a 1+ °C per century linear trend.

Note that the doubled value, 560 ppm, will be reached in 100 years from now (2109) because

560-385 ppm = 175 ppm = 1.75 ppm x 100

and the rate around 1.75 ppm of added CO2 per year seems to be pretty constant for quite some time. In the next 100 years (2009-2109), I expect 0.6 °C warming from the increased CO2 concentrations, assuming business-as-usual for 100 more years. This contribution will be lost in the noise of many other contributions of both signs. And it makes no sense to extrapolate the calculation beyond 2109 because people in 2109 will surely make their own decisions. Moreover, it is likely that their dependence on fossil fuels may already be reduced and new technologies to produce energy (or manipulate the climate) may be available.

Richard Lindzen says that the net climate sensitivity is only 1/2 of my "neutral" value (or less) and I don't quite understand his calculation. But let's admit that it would be extremely difficult to distinguish the two figures by measurements in the 21st century because those 0.3 °C of difference are hidden in the noise of dozens of other effects.

More importantly, I think that even my "neutral" answer, 0.6 °C of warming per century, clearly poses no threat to us or other life forms on Earth. After all, we have seen the very same warming in the 20th century (our CO2 output has increased, but the effect of each CO2 molecule has dropped, because of the logarithmic law) and there have been no detectable negative consequences of it for the Earth whatsoever. It is therefore extremely awkward to expect something dramatic to happen from the same small increment repeated once again.

I may expand this text later.

PAMELA: excess of 1.5-100 GeV positrons

Click the picture to see the experiment's website

As you have been already told when we talked about the CDF lepton jets, the PAMELA collaboration has detected an excess of positrons at energies above a few GeV, especially if they approach 100 GeV, their measured maximum.

These positrons can't come from secondary sources. While the theoretical percentage of positrons from secondary sources among electrons and positrons drops from 5% to 2% between 5 GeV and 100 GeV, PAMELA indicates that the fraction increases from 5% to 15%.

They must arise either from primary astrophysical sources (such as pulsars) or from dark matter annihilation (for example from neutralinos, the prime dark matter candidates, or even winos - if our world is supersymmetric).

Links:

• Full text
• Nature (abstract)
• Google News

Hat tip: Marco Frasca

RealClimate.ORG abolished

As some of you may have expected, some members of the RealClimate.ORG have always been sane. They have evaluated the Heartland Institute's conference of climate realists and determined the the science is settled.



The realists have always been right, the group now says, which is why their propagandistic website, RealClimate.ORG, can finally be abolished:

Farewell to our readers

Even Rajendra Pachauri of the IPCC has eaten a couple of steaks and revived most of his sleeping neural vegetarian cells in his brain:

Scientists worldwide admit global warming is a hoax

Al Gore has finally urged the police to put him in the prison, too. So everything starts to make sense and people who have been considered brain-dead for many years are becoming a part of our society.

In related news, Peter Woit and Lee Smolin (who just solved the cosmological constant problem today, together with Chandra Prescod-Weinstein, extending methods of Marco Polo) have understood why they have been obnoxious crackpots for many years, they have apologized to everyone whom they have hurt during all those years, and offered all of their resources in an attempt to undo some of the most immoral acts that they have been doing for such a long time.

Congratulations - one day is enough and pretty much everything in the world starts to work properly! The newest developments also prove that Sean Carroll was right that the arrow of time can flip at any moment: high-entropy, oxidated brains can always undo the disintegration process and become healthy once again.

The Bogzabraloff brothers were interviewed by an out-of-equilibrium journalist. ;-)

Google has finally released the 3D version of Google Chrome (download) and they are planning to introduce the remaining 6-7 dimensions later in the year. Sabine Hossenfelder's double brother-in-law, Robert Scherrer, has proven the basi