Sunday, August 31, 2008 ... Deutsch/Español/Related posts from blogosphere

Emergent gravity: positive and negative insights

A conference at MIT was dedicated to emergent gravity and I find the approaches of a vast majority of the participants (except for Subir Sachdev, who was talking about AdS/CMP) to this question unreasonable and hopeless; see the program and "Emergent Gravity" at a European physics blog for a report. As Moshe Rozali wrote, it is strange that no string theorists were invited, especially because many actual experts on emergent gravity were present in the same MIT building during the conference.

It is possible, and in fact likely, that the metric tensor - a set of fields introduced to physics by Einstein that define the spacetime, its dynamical geometry, and that underlie the gravitational force (because it results from the spacetime curvature) - is not a truly fundamental entity.

See also: Emergent space and emergent time (2004)
But it is very important to know some "details" how the gravitational force is actually supposed to emerge. There are two basic classes of approaches to the mechanisms of emergence:
  • Preconceived, simple ideas that "should work" but they have never worked when their details were investigated (but people are often not ready to give up)
  • Unexpected ideas that people didn't consider a few centuries or decades ago but that naturally emerged in some equations of physics and they actually do work (but people are often afraid to study them too much and to go too far from the old tracks)
Quite clearly, your humble correspondent denounces the first group while the second, mostly string-theory-based group is thought to be very important.

Very generally, different researchers and their teams may try different approaches. But their research should never stand on increasingly shaky and unlikely pillars. Every scientist may have a slightly different interpretation of the existing evidence. But his assumptions shouldn't become crazily unlikely: he should still rationally evaluate the available evidence. I will dedicate six more paragraphs to this sociological question, before I return to emergent gravity.

Some people say that different approaches to similar questions should be "supported" by the society. What they mean is that every scientist should try to assume whatever he wants, even if it looks extremely unlikely (and maybe even increasingly unlikely) given the available evidence, and bureaucrats or politicians are those who should ultimately regulate the number of people who study various approaches (via funding), probably depending on their P.R. departments.

I completely disagree with this kind of a "scientific method". If we talk about the real science, every researcher should individually try to obtain the right answers about the reality, instead of looking for biased answers, hoping (or claiming to hope) that his or her bias (or the bias of his or her team or community) will be compensated by others. Even when it comes to the very big questions - and, in fact, especially in the case of the big questions - scientists should try to evaluate the existing evidence as well as they can to decide which research approach they should choose. To do so, they must know at least something about the "competing" approaches. They should never leave the big questions to the bureaucrats or politicians because the big questions are a part of science, too (in fact, the most important one).

For example, it is foolish for a scientist to dedicate a whole life to an idea (with unspectacular consequences) if the probability that the idea is correct is much smaller than 10^{-10}, the inverse population of Earth.

Why? You can see that the contributions of such a scientist to science are likely to be negligible. How can you see it? Multiply his contributions by the population of Earth. This product now includes all the scientific work of mankind but it is still unlikely that at least one idea investigated by at least one person is correct. So even the expected value of the results obtained by the whole mankind would be pretty small: they would probably not find the correct theory in their lifetime. What one person is doing is 10^{10} times smaller so the value is really tiny.

It means that if scientists study pretty much the same problem - e.g. quantum gravity - they must be interested in all relevant arguments and evidence, instead of segregating themselves into different "fields". More concretely, loop quantum gravity is not a "different field" than string theory. Loop quantum gravity is the same field as string theory, namely quantum gravity - the only difference is that it is done by people who can't properly evaluate the scientific evidence and they end up with wrong answers. Unfortunately, they don't seem to care about real physics and real evidence whenever it shows that they're doing something incorrectly.

In the very same way, it is not true that string theorists should "isolate themselves" from the attempted alternatives. They should know what the alternative approaches are saying and they should have a qualified opinion about it. If they think that the alternative approaches are likely to be true or that they say something important, they should incorporate it in their work (or to completely change their approaches). If they think that the alternative approaches are simply incorrect, as I do, they should behave according to this conclusion, instead of being "nice" and support a wrong answer (and huge amounts of wasted man-hours and dollars paid to this hopeless approach). There is nothing "nice" about supporting bullshit.

Fine. Let me stop with sociology and return to the mechanisms of emergent gravity.

How space emerges in string theory

The oldest example began in 1919. Let me assume that the reader knows what the Kaluza-Klein theory is, at least at the level of Chapter 4 of The Elegant Universe.

Kaluza-Klein paradigm

In Kaluza-Klein theory, one can relate higher-dimensional theories to lower-dimensional theories by the trick (or mechanism) called compactification. There are two types of a description of a physical system in this context: the higher-dimensional one and the lower-dimensional one.

In the higher-dimensional description, one assumes that there exists a rather simple theory - for example, a field theory with a small number of fields - that is defined in a higher-dimensional space. In Kaluza's original example, a five-dimensional spacetime was equipped with pure Einstein's gravity.

The lower-dimensional example is "simpler" in one sense only, namely that the spacetime dimensionality is smaller. However, it has many more degrees of freedom. For example, in the original Kaluza-Klein theory, you need to Fourier-transform the five-dimensional fields over the fifth dimension. The individual Fourier modes generate a tower of infinitely many mostly massive four-dimensional fields. Their precise interactions are constrained - the infinitely many masses and interaction constants are linked to each other - because they remember their five-dimensional origin. So you can view this physical system as a four-dimensional theory but it is a special type of a four-dimensional theory, with infinitely many fields and infinitely many constraints on their properties.

Kaluza's original idea was to unify electromagnetism and gravity, the only two forces that the anti-quantum physicists of his era (such as Einstein himself) found worth studying. Qualitatively speaking, the idea worked - after the corrections by Klein who really realized and appreciated that the extra dimension was compact. However, using quantitative laws, the simplest version of the idea could have been ruled out rather soon. Note that the Fourier expansion is something that the ancient Greeks didn't understand well: it was only invented two centuries ago.

In string theory, the idea was generalized and a generalized Kaluza-Klein theory is compatible with several classes of realistic models of the real world within string theory. What are the generalizations? Well, first of all, the compact dimensions don't have to be a circle. They can be multi-dimensional shapes, such as the Calabi-Yau manifolds. The Fourier expansion has to be replaced by the expansion into the eigenmodes of some more general operators. More complicated shapes, such as conifolds, orbifolds, non-Kähler manifolds, warped throats, non-geometric compactifications, or many others have been studied and fascinating, coherent insights have been found in most cases.

But string theory has generalized the concept in many other ways that couldn't have been expected at the beginning. For example, the integer label distinguishing the different Fourier modes can have many interpretations. In the Kaluza-Klein theory, it has to be the momentum along the compact (fifth) dimension. In string theory, it can often be represented as a winding number or a wrapping number of strings or branes in a dual description.

Because of this unexpected property, new dimensions of space may emerge out of completely new phenomena. If there is a very short non-contractible circle in your compactification, strings can be winding around it many times. The winding number (how many times they're wrapped around the circle) becomes effectively continuous and can be reinterpreted as the momentum in a new dimension that becomes a new, large, effectively non-compact circle.

This phenomenon is called T-duality (and it can be rigorously proven in perturbative string theory). Compactifications on very short and very long circles are equivalent to one another once extended closed strings are allowed to wrap these circles. And they must be allowed to do so because an unwound string is always able to pair-create two opposite wound strings (as long as any interactions are allowed at all). T-duality can be applied to several independent circles in the stringy geometry: mirror symmetry is a remarkable example of a triple T-duality that relates two beautiful, but a priori unrelated six-dimensional Calabi-Yau shapes.

In principle, you could imagine that the whole three-dimensional space around us (let me omit time now; this limitation was discussed in the 2004 article) can arise from a conspiracy of many particle species in 0 dimensions. In this sense, the whole space is emergent. However, there are many ways how infinitely many objects in 0 dimensions can interact with each other. The knowledge of their higher-dimensional origin, or something equally constraining, is clearly necessary to find realistic quantum mechanical models in 0 spatial dimensions.

Just by saying that physics in 3 spatial dimensional is equivalent to a system in 0 dimensions, you haven't solved much. But indeed, we know several ways how physics of a field theory (or something that is approximated well by a field theory at long distances) in many dimensions can naturally be rewritten in terms of a theory in 0 dimensions. The BFSS matrix model is an example. However, we needed to know a lot about the higher-dimensional physics to find such a special model. Almost every "obvious" modification of the BFSS matrix model ends up with a quantum mechanical model without any higher-dimensional interpretation.


Holography is another, and perhaps even more famous example of emergent dimensions. In the case of Kaluza-Klein theory and its generalizations, we didn't have to rely on gravity. T-duality works even before gravity gets turned on. However, holography - the equivalence of a gravitational theory in D+1 dimensions and a typically non-gravitational theory in D dimensions - does depend on gravity very strongly. Why? Holography is related to the entropy bounds: the maximum entropy one can squeeze into a given volume is achieved by a black hole and the resulting maximal entropy only scales as the surface of the region, and not the volume as you might expect, in Planck units. And black holes need gravity to exist.

The anti de Sitter space is the most specific and successful realization of holography in action, because of Maldacena's AdS/CFT correspondence. The "bulk" of the anti de Sitter space is emergent here: we can describe its physics in terms of a theory that only lives on the boundary of the space (at infinity, in this case).

You might think that it is just another example of the Kaluza-Klein paradigm: we are making some kind of Fourier transform over the extra (radial, holographic) dimension. You might think that the boundary theory will have "infinitely many" fields of the Kaluza-Klein type. But you would be essentially wrong. The boundary theory is extremely simple - in the case of AdS5/CFT4 duality, it is a cousin of QCD: an ordinary gauge theory with a finite number of "elementary matter fields".

Now, the infinite tower of fields that we knew from the Kaluza-Klein case hasn't quite disappeared. You can still create infinitely many fields but they are composite fields. For example, excited strings in the bulk are created by various composite operators in the QCD, analogous to Tr(ZZZAZZZZB), the BMN operators. However, the very momentum along the holographic dimension is not encoded in this way. The reason is that the boundary theory is non-gravitational and it also includes off-shell, local Green's functions: you can study correlators of operators represented by Feynman diagrams where the external particles don't satisfy the expected energy-momentum-mass dispersion relations. However, the equivalent theory in the higher-dimensional bulk is gravitational and only knows about the on-shell scattering amplitudes. It is meaningless to ask about the local, off-shell Green's functions of the gravitational theory in the bulk: this fact is indirectly related to the holography itself.

Other mechanisms

Kaluza-Klein theory and holography are just two examples how dimensions may emerge - and transform into something else - in string theory. I should also be talking about topology transitions, quantum foam in topological string theory, deconstruction, and many other interesting mechanisms where dimensions of space emerge from something else. Gravitons themselves are emergent in perturbative string theory because they are closed strings in a particular vibration mode: see Why are there gravitons in string theory.

However, if I started to talk in this way, I would never stop because all of string theory may be viewed as a generalization of gravity that is emerging from something else. For example, all closed string modes may be thought of as components of a gigantic stringy "gravitational multiplet" and all other branes are generalizations of a string (and they can be dual to strings in various dual descriptions). There is no way to strictly separate "geometry" from "non-geometry" in string theory. This statement shouldn't be surprising because it is really equivalent to the fact that string theory unifies gravity with other forces (and matter).

But some people don't realize that these statements are equivalent because they assign similar propositions with emotional labels. Unification is good, so it should exist, but a separation of geometry from non-geometry is also good, they think. Well, it's no good because such a separation would be the opposite thing than unification and unification is good, indeed. ;-)

In string theory, all concepts we know are kind of linked to each other and all of them may be viewed as generalizations of geometry (a quantum, stringy geometry). Moreover, the combinatorial graph indicating how different fields, objects, and concepts in string theory are linked to geometry (and to each other) is not a tree graph. It has loops, too.

For example, the dualities (equivalences between various stringy vacua) link all the theories (and their objects) into a complex multi-loop network. Each loop implies a non-trivial prediction - a consistency check similar to the transitivity conditions for the transition maps on a manifold. And all these consistency checks have worked well, so far: they are almost as powerful as experimental tests in proving that this is a theoretical structure that a theoretical physicist simply has to care about. It is a beautiful, robust structure. And this whole structure may be interpreted as a generalization of Einstein's general relativity in which the right tools to generalize have been fully exploited.

So instead of talking about all ways how space (and time?) can emerge and transform in string theory, which is what all the conceptual efforts in string theory research (thousands of papers) are focusing on, even if they don't say so explicitly, let me return to the bad type of the research of emergent gravity.

Discrete and condensed-matter gravity

Some people are very impressed by the unexpected ways how macroscopic pieces of material can exhibit new types of behavior in condensed matter physics - superconductivity, superfluidity, Fermi liquid, highly correlated fermions, metals, fractional quantum Hall effect, and so on. I have surely missed some of the best examples.

I am also impressed except that Nature doesn't guarantee that similar ideas will work at many places. Some places need completely different ideas and we can often see what they are.

Other people talk about discrete physics, imagining that a finite volume of space is always made out of a finite number of easily visualized, "discrete" elementary building blocks. The space is a spin network and the spacetime is a spin foam (or a causal dynamical triangulation), they say. For some philosophical reasons, they find such a philosophical picture pleasing. But in physics, something's being philosophical pleasing is an entirely different criterion from something's being physically correct.

Assuming that something is only composed out of discrete blocks is a huge assumption - much like the assumption that a random, measurable, a priori real quantity will be integer-valued. It is very unlikely that it will be integer-valued. In the very same way, it is very unlikely that all of physics may be encoded in "discrete" quantities (even though, in some cases, both situations can occur - but there is usually a well-known argument, not just wishful thinking).

More concretely, these discrete descriptions of space suffer from a couple of very general problems. They almost always break the Lorentz invariance which is always a huge problem because the Lorentz invariance is one of the key experimentally verified principles underlying modern science (special relativity is crucial in particle physics). They violate the Lorentz invariance because the vacuum is not really "empty". It contains a new kind of luminiferous (or gravitiferous) aether. Consequently, one expects that a privileged reference frame is picked.

Moreover, the aether seems to have a huge entropy density - probably the Planckian entropy density if the building blocks have Planckian dimensions. Such a huge entropy carried by the vacuum would completely destroy thermodynamics (for example, it would cause a huge friction because such a "vacuum" resembles a highly viscous liquid) as well as interference in all interference experiments (because the microstates of the vacuum are distinguishable and they can't interfere with each other). It would also spoil the Lorentz invariance by itself because the entropy density is a time component of a four-vector (am entropy current) and its nonzero (huge) value is non-invariant under the Lorentz transformations, too.

For the typical composite theories of space, one can show that these problems are real and huge. The Lorentz violation in these theories is not "small" in any sense. Among many other problems, this bug also makes perpetuum mobile possible. ;-) The only method how to achieve a tolerable situation is to have a system whose vacuum can be shown to be fully equivalent to a traditional "empty vacuum" in a Lorentz-invariant field theory. If you can't see a reason why such an equivalent description should exist, it almost certainly doesn't exist and your composite theory is ruled out because it disagrees with some extremely basic features of our world such as the "emptiness" of the vacuum (e.g. the absence of friction in the vacuum).

There are other huge constraints that make similar composite models of a graviton impossible. The Weinberg-Witten theorem is a textbook example of these no-go theorems. These two extremely famous physicists have shown that composite massless particles with spin exceeding one cannot exist; in fact, even theories with an elementary particle with spin above one cannot be renormalizable local quantum field theories.

This result is a "negative" one in the sense that it kills someone's hopes. But I am among those who view negative results to be as important for science as positive results. Whenever we understand how Nature doesn't work, we also understand something about the way how it does work. These "negative" results usually lead to a reduction of research activity in a certain direction which is why many people don't like them. They steal "jobs" from the people. But this is not an objective, unbiased criterion. I think it is great if you can save man-hours in this way! If you get rid of the bias, positive and negative true insights are equally valuable.

Needless to say, in the real world, not quite all such man-hours are saved. Many people continue to investigate theories that directly contradict some of the known no-go theorems. The perpetrators usually don't understand the no-go theorems well. Most typically, they either ignore the theorem completely or they invent some bogus explanations why their theories shouldn't be subject to these no-go theorems (recall e.g. Garrett Lisi's bizarre "explanations" why he doesn't care about the Weinberg-Witten theorem).

If these people were sane, they would realize that their explanation why they "can" circumvent the no-go theorem could be used by the author of every single composite graviton theory (for example, everyone could say that at the end, they want to add a positive cosmological constant, which is a subtlety that Weinberg and Witten didn't take into account, they emphasize).

Consequently, it would follow that the Weinberg-Witten theorem is completely vacuous and the authors themselves, Weinberg and Witten, would have to be completely deluded. For some reason, the "composite gravity" geniuses don't see any problem with such an inevitable conclusion of their thinking. Now, the thing that irritates me is not that someone is ready to believe that Witten and Weinberg are deluded and that they write vacuous theorems. Feel free to believe so. But you are still wrong because the theorem is actually very powerful.

For example, the cosmological constant is completely irrelevant and you can see that it can't change the conclusion (that the composite graviton theories are ruled out). The vacuum energy only creates errors of relative magnitude 10^{-120} or so, altering the conclusions from the flat space. But the composite character of gravitons induces much greater errors - of order one - so they can't cancel. These problems - the cosmological constant and the compositeness - have nothing to do with each other.

I think that whoever tries to study similar "composite" theories should carefully read the Weinberg-Witten paper and learn their methodology. He or she should try to apply and modify similar reasoning for his or her context, too. And I assure you that it is not hard to modify the Weinberg-Witten arguments so that they can rule out every research direction in which the "gravitons" or the "metric tensor" are composite fields in the bulk of spacetime (that is however non-emergent).

String theory guides us to the right highway

String theory is able to circumvent the theorem in very unexpected ways, for example in the AdS/CFT correspondence. The reason why gravitons can be emergent or associated with composite operators is that it is not only the gravitons that are emergent: it is a whole dimension of spacetime (or more) that emerges, too. Such a broader process of emergence is harder to imagine a priori which is why people haven't tried it before the phenomenon was understood by string theorists (who tried to understand why some consistency checks concerning black hole entropy worked better than they expected).

So it is fair to say that most of the "very minimal" and "philosophically pleasing" pictures how gravity, geometry, and other things may emerge can be falsified. On the other hand, string theory exactly tells what kind of non-minimal extensions of these ideas you should pursue in order to have a chance that your theory won't be instantly ruled out.

There are lots of examples of this phenomenon - that string theory is able to "guide you" in finding many non-trivial and non-minimal mathematical structures and theoretical frameworks that share some features with the "cool and simple ideas" that you might invent after a few minutes but, unlike the cheap and fast ideas, these non-minimal ideas work. We can check that they do achieve what they claim.

For example, you may imagine that Cartan, Killing, Dynkin, and others wouldn't have been able to classify Lie groups and to find the exceptional ones. Nevertheless, string theory could have been discovered even without this insight. After a few years, they would also find the heterotic string theories and realized that one of their versions has 248 copies of a massless gauge field. They would be inevitably led to the E_8 group (and there are other constructions that are natural in string theory that lead you to E_8). Soon afterwords, they would discover the other exceptional groups as the subgroups of E_8.

There are many other, more complex examples of this kind that are behind the popular phrase that "string theory is smarter than us". For example, supersymmetry, a new symmetry that, morally speaking, circumvents the Coleman-Mandula no-go theorem (implying that symmetries that non-trivially mix the spacetime symmetries with the internal ones are impossible), was found in the context of string theory, too. It was sufficient for Pierre Ramond to try to incorporate fermions into the old bosonic string theory. He found both the superstring as well as the (worldsheet) supersymmetry.

Just like the experiments have often been necessary for the theorists to realize certain things that they could have discovered by pure thought (by they didn't), string theory is able to do the very same thing. It often helps us to search for a "needle in a haystack" even though we often find the farmer's daughter instead - i.e. we find a non-trivial, non-minimal construction similar to other constructions that have been looked at, except that the people were not able to combine all the right ingredients to make it work.

Even though Nature and string theory are demonstrably smarter than us, and smarter than Einstein and others, some people still try to be smarter than Nature and string theory. The only problem is that their attempts never work. The airplanes don't land. Virtually no interesting constructions - potentially relevant for Nature's mechanisms at the fundamental level - have been discovered in this way and most of the people who continue to investigate e.g. the emergent gravity - while the spacetime in their framework is not emergent by itself - are stuck with some excessively simple theories that have already been falsified.

Meanwhile, string theorists keep on finding fascinating new things, by making their careful "experiments" with string theory. These new discoveries have existed in the abstract Platonic world of cool mathematical ideas and they have only been "discovered". Certain people may feel happier if they "invent" completely new things except that this approach, while useful in engineering, hasn't led anywhere in theoretical physics. Nature can't be "invented". Its secrets already exist out there and we are only allowed to "discover" them. To do so, we must listen to Nature - through the experiments or string-theoretical calculations - in the right way to hear what She is trying to tell us.

You may try to be smarter than Nature but you will eventually fail because She rocks.

And that's the memo.

P.S.: A particularly silly viewpoint on gravity will emerge in 2010 when Erik Verlinde will claim that gravity is an entropy-driven force.

That can't be the case. Such a "LeSage theory of gravity" would imply that the gravitational phenomena are inevitably irreversible and that they don't apply to individual particles because they would destroy the interference patterns.

However, gravity works even in microscopic experiments, neutron interferometry has shown that the whole pattern is moved exactly as you would expect from a "freely falling" wave function. And gravitating bodies don't lose energy and don't create any macroscopic entropy. Erik Verlinde's picture is born as a dead baby.

Saturday, August 30, 2008 ... Deutsch/Español/Related posts from blogosphere

Sarah Palin & global warming

McCain chooses Palin as his running mate (playlist, 4 parts)

Sarah Palin (44), the governor of Alaska, and her life surely look fascinating and she will probably make McCain's GOP ticket much stronger (and certainly much younger! McCain is 72 today). She is a former beauty queen, ex-mayor, former sports reporter, hunter, shooter, fisher, wife of an Eskimo, pro-life feminist, mother of five, including a bundle of joy with XX+21.

But she's a great character.

There are all kinds of interesting things about her but because climate and energy policies are among the standard topics on this blog, I chose the video above. In this June 2008 Glenn Beck show, she talks about her lawsuit against the U.S. government that wanted to use the "endangered" polar bears as hostages to cripple her, Alaskan economy and to prevent them from tapping the resources, because of some unreliable climate models, as she calls them. She appears at 4:30, after an entertaining anti-environmentalist rant by Glenn Beck.

See also:

Palin not convinced on global warming (The Washington Post)
Palin: global warming not man-made (ABC News blogs)
Interview on McCain, abortion, climate change (NewsMax)
She has also serious doubts about Darwin's biology but I feel that alarmism is more serious a threat to the humanity these days than creationism. In the interview linked above, she answers the following to the last question about the impact of climate change on America and Alaska:
A changing environment will affect Alaska more than any other state, because of our location. I'm not one though who would attribute it to being man-made.
Oops, they just deleted Wikipedia's global warming skeptics category.

If you're in the process of launching your own site dedicated to
global warming skeptics, Sarah Palin, or both, you'll need to find affordable website hosting. You need look no further.

Friday, August 29, 2008 ... Deutsch/Español/Related posts from blogosphere

Bell Labs' fundamental physics research: RIP

Bell Laboratories decided to close their fundamental physics research.

Google News
That includes basic science, material physics, and semiconductor research. Because of short- and medium-term financial reasons, they will focus on networking, high-speed electronics, wireless technologies, nanotechnology, and software.

The discoveries made at Bell Laboratories, the research organization of Alcatel-Lucent, have shown the amazing creative power of the American commercial sector. Their achievements have led to six physics Nobel prizes, for
  1. demonstrating the wave nature of matter (Davisson 1937)
  2. transistors (Bardeen, Brattain, Shockley 1956)
  3. electronic structure of glasses and magnets (Andersson 1977)
  4. cosmic microwave background (Penzias, Wilson 1978)
  5. laser-based cooling and trapping of atoms (Chu 1997)
  6. fractional quantum Hall effect (Stormer, Laughlin, Tsui 1998)

CERN beats German LHC alarmists

It should be a trivial news that doesn't require any report except that in this crazy world, it does. ;-)

Court saves the LHC from Otto Rössler et al.

Boltzmann brains: popular misconceptions

Today, there are two anthropic hep-th preprints concerned with the so-called "Boltzmann brains". One was written by Bousso, Freivogel, and Yang, while the other was constructed by De Simone, Guth, Linde, Noorbala, Salem, and Vilenkin.

Many of them are big names, we like them, yet the papers are obviously wrong. Every individual sentence in the abstracts of these two papers actually seems to be incorrect by itself. The same comment applies to most sentences in the bulk of the papers. They use all kinds of wrong proportionality laws between the "volume" and the "probability" - the kind of laws that small pupils believe when they hear about the first proportionality laws in their science classes. Everything is proportional to everything else, isn't it?

Well... No, it's not. But let me start with some comments about:

Boltzmann brains

The entropy of a system never decreases "macroscopically", at least not "systematically" for long periods of time. This observation is called the "second law of thermodynamics", it underlies the so-called (thermodynamic) arrow of time, and using general methods of logic and statistical physics, it can be proven to hold in any physical system that admits macroscopic changes of the entropy: see the previous article about the second law.

And if the entropy does decrease for a while :-), the probability that such a thing occurs decreases exponentially with the total decrease of the entropy: when other things are "equal", whatever it exactly means, the probability goes like exp(-|entropy_jump|) which can be an impressively tiny number. Whenever you (approximately) say that the entropy is "macroscopic" (i.e. a large multiple of the tiny Boltzmann's constant, a number that is not too far from Planck's constant), it is effectively infinite in the natural microscopic units, and the probability of such an evolution is zero.

Thursday, August 28, 2008 ... Deutsch/Español/Related posts from blogosphere

Long-term predictions and wishful thinking

I was trying to understand the ideological framework that leads so many people in the West to dismiss Russia as a "country in decline" exactly at the moment when it's rising from its knees, regaining its lost self-confidence, and surpassing the world in the GDP growth as well as in its military flexibility and readiness.

It seems that this ideological framework is a conglomerate of at least five general fallacies that also appear in many other contexts and that I would like to analyze. The only "objective" comment against the impressively good and promising condition of current Russia that I have fully understood is its negative population growth. Well, in 2007, there were 11.3 births per 1,000 people in Russia, more than 10.7 in the U.K. but less than 14.2 in the U.S. At any rate, there's not much difference here. Because of the lower life expectancy, there are more deaths per 1,000 citizens in Russia. But all these numbers, especially the birth rate, are flexible and can change.

However, the critics of Russia seem to be certain that in 2050 or so, Russia will be going down. Moreover, this idea influences their opinions about the "right" behavior that the Western politicians should adopt today. Fine, so let me first enumerate the (corrected) fallacies, before I will discuss them in detail, together with many other examples of these fallacies:

  1. It is irrational to try to predict demographic subtleties in the very long run, e.g. in 2050
  2. Even if it were possible to predict these things, they shouldn't significantly influence rational decisions in 2008, especially not our "perception of justice"
  3. Even if the trends in 2050 could be predicted, it is irrational to assign them with positive or negative moral labels
  4. Even if a quantity could be expected to be in "decline", it surely doesn't mean that you can imagine that it will be zero any time soon
  5. When a rational person applies a certain kind of predictive methods and assumptions to one nation (or other subjects or objects), he should do so consistently with other nations (or subjects or objects), too.
Fine. So let me discuss these issues in detail.

Tuesday, August 26, 2008 ... Deutsch/Español/Related posts from blogosphere

GLAST renamed for Fermi: first results

Audio (since 2 p.m. EDT = 8 p.m. Prague Summer Time; RealPlayer needed)
A web page of the press conference
GLAST home page
GLAST prelude (MP3; explanation here)
Just two months or so after GLAST was launched, we will be told about the first results. They will also announce the new name of GLAST: it's Fermi.

The first result is that the gadget seems to be working very well and the luminosity is amazingly promising. Give us ten years, they say. There's a message for all Horgans, Woits, Smolins, and similar stuff from Dawkins: science is interesting and if you don't agree, continue with this video (context). ;-)

Via Tommaso Dorigo.

Glashow: blind chance or intelligent design

Playlist (3/17, an hour in total)
Glashow talks about the crucial interplay between unexpected discoveries and planned research in science. He demonstrates the point on many historical examples. Serendipity means to look for a needle in a haystack but to find the farmer's daughter instead. ;-)

The parts 1/17 and 2/17 are a bureaucratic self-promotion of Honeywell and China but you can see them, too. ;-) At the end, there are some questions. For example, a girl asks Glashow why he switched from literature. It turns out that her assumption followed from a degree Glashow earned, "Bachelor of Arts". :-)

Monday, August 25, 2008 ... Deutsch/Español/Related posts from blogosphere

Russia recognizes independence of Abkhazia and South Ossetia

The upper house of the Russian Parliament (Council of Federation) has voted unanimously (130-0) to ask President Medvedev to recognize Abkhazia and South Ossetia as independent countries. By the rules of statistics, it could have been expected that the lower house (Duma) would do the same thing soon: it voted unanimously (447-0) a few hours later.

Medvedev will have to think twice. The recognition of their independence would mean a change of their policy: they opposed the independence of Kosovo. But because the world, including Russia, is slowly accepting that Kosovo has become an independent country, the situation has changed.

Update: Medvedev recognized the countries on Tuesday (video: speech)
I would find it natural (and more stable) for Russia to recognize the independence, organize a speedy referendum, and attach those provinces to the Russian Federation. At least that's what I would be doing as the boss of the Kremlin. A re-unification is particularly natural for Ossetia.

Sunday, August 24, 2008 ... Deutsch/Español/Related posts from blogosphere

Richard Dawkins & Steven Weinberg on religion and science

Playlist (8 parts, 85 minutes)
These two prominent atheists, of course, share a lot of opinions. But you can see some funny differences: for example, Dawkins thinks that the anthropic explanations are "elegant".

Saturday, August 23, 2008 ... Deutsch/Español/Related posts from blogosphere

Joe Biden and global warming

Barack Obama will pick Joe Biden as his running mate. When it comes to climate change, Biden seems to be just another mad man:

Face global warming or global conflict (2-page interview)
As a presidential candidate, he said that global warming will destroy the U.S. military. He is the "best one" to solve the "energy crisis" and wants to reduce CO2 emissions by 80% by 2050 while raising the mandatory percentage of alternative energies to 20%, among many other mad things.

Friday, August 22, 2008 ... Deutsch/Español/Related posts from blogosphere

Strings 2008: Friday

You may go to the main Strings 2008 page on this blog; that page includes the live webcast.

Thursday, August 21, 2008 ... Deutsch/Español/Related posts from blogosphere

Strings 2008: Thursday

You may go to the main Strings 2008 page on this blog; that page includes the live webcast

Warsaw Pact occupation of Czechoslovakia: 40 years later

Video 1: Pictures mostly from Prague. The sound features (otherwise patriotic) radio hosts who are telling the people that it makes no sense to resist physically because the invaders are far too strong - a theme about "adaptation" that we've known at least since 1938. ;-) So Czechoslovaks were at least trying to twist the traffic signs to confuse the foreign soldiers and inventing anti-Russian jokes: see another (moving) video. Prague became the most civilized city in the world to be occupied by tanks since 1945.

See also: Obama's 4-minute speech about the anniversary
Exactly 40 years ago, in the early morning of August 21st, 1968, the Warsaw Pact tanks invaded Czechoslovakia, occupied the country in a perfectionist Blitzkrieg operation, and ended the Prague Spring, a period of democratization, liberalization, and socialism with a human face.

I deliberately didn't say that it was the Soviet troops. Among the 200,000 troops, you could find 28,000 Poles - quite a huge percentage. The Russians were only a majority because they were a majority in the Soviet bloc, too. Besides the Soviet Union and Poland, the other countries that participated were Bulgaria, East Germany, and Hungary. Ceaucescu in Romania refused to send troops, and so did Yugoslavia and Albania (the former was the only country that mobilized, in support of Czechoslovakia, thanks a lot, while the latter left the Warsaw Pact because of the incident).

The utopia of democratic socialism

Around the middle 1960s, Czechoslovak communism started to "soften", in a huge contrast to the brutal executions and fundamentalism in the 1950s. Perestroika-like economic reforms were adopted: Mr Ota Šik of Pilsen was the architect of the new economic plans. In 1968, Mr Alexander Dubček [pronounce: Doop-Czech] of Slovakia was chosen as the new boss of the communist party and democratization began, too. Free press and hundreds of types of activities started to flourish. This year is referred to as Prague Spring.

You should realize that the Czechoslovak economy of the 1960s was still comparable to the Western economies and a smooth transition to capitalism - that could naturally follow from the democratic socialism - could abruptly return us to the Western world where we belonged for the previous millenium.

The "nice" communists were, of course, dreaming about the preservation of communism, just making it human, efficient, and so forth. Today, it is widely accepted that such an idea was a utopia. Socialism is inherently incompatible with democracy and freedom. Socialism has to mess up with basic mechanisms regulating a free society: it wants to create unnatural conditions. To do so, it must always adopt some totalitarian techniques, to one extent or another. But a democratic socialism could have been just the first step towards normal democracy and capitalism, of course.

In my opinion, Dubček was a decent, likable guy but a naive politician. After the Velvet Revolution in 1989, he was naturally a possible candidate for the president of Czechoslovakia. But there were all kinds of problems with him because his speeches still sounded like communist speeches, in a sense. When Dubček learned in December 1989 that Václav Havel was chosen as the Civic Forum's presidential candidate instead, he started to cry like a small girl. He was not ready for real competitive politics in a democratic country. A few years later, he died in a car accident. As a yellow cab driver in Boston once told me, he was killed by the "multi-nationals" :-) which sounds funny but what do I know?

Getting ready for the occupation

What happened before the occupation began? As we learned in the early 1990s when former President Havel was given some secret letters from the Russian government, five Czechoslovak communist traitors (Biľak, Švestka, Kolder, Indra, and Kapek) wrote a letter to the Soviet authorities claiming that
"... right-wing media [were] fomenting a wave of nationalism and chauvinism, and [were] provoking an anti-communist and anti-Soviet psychosis." It formally asked the Soviets to "lend support and assistance with all means at your disposal" to save the Czechoslovak Socialist Republic "from the imminent danger of counterrevolution."
Mr Biľak gave another version of the letter to some Ukrainian guys, during a meeting organized by KGB. Well, these were important enough communist puppets for the Soviet (and other) politicians to act. I kind of understand that they did. In this sense, I prefer to blame the Czechoslovak traitors more than the foreign communist politicians. But the very communist system was the primary reason why these events took place.

I will never accept the nationalist, anti-Russian interpretation of all these events. The Prague Spring and the occupation that followed were about the tension between the freedom and totalitarianism. The totalitarian ideology has been connected with all kinds of nations. Marx was German, Lenin was Russian, Stalin was Georgian, Mao was Chinese, and Che was Argentine. Czechoslovakia always had its own communists who were the key for the rise of hardcore communism both in 1948 and in 1968.

Moreover, Russia has done good things for us, too - including the liberation of most of the country from Nazism in 1945. In my opinion, currently fashionable inherently anti-Russian positions (that moreover judge two isomorphic situations very differently, depending on the role of Russia in these two situations) are analogous to the German anti-Semitism during holocaust: they are racist in essence and I am shocked that the people with those opinions don't realize it.

The defeated player in the Cold War was communism, not the Russian nation, and as soon as Russia adopted its kind of democracy, the "reparations" have been paid. There exists no justification for an additional "punishment" against Russia. I have a lot of respect for numerous people who enjoy their childish anti-Russian image but when it comes to wars (such as the recent war of Georgia against South Ossetia that backfired, as wars often do), it's just damn too serious if someone is not able to judge the situation fairly.
Pat Buchanan writes about the natural reactions of a provoked bear: I agree with him completely
But let's return to the events in 1968. After the invasion, freedom, optimism, and national pride were slowly dying away. A few smart students burned themselves to protest against the Czechoslovak defeatism. Some people were thrilled in January 1969 when Czechoslovakia beat the Soviet Union in ice-hockey and they destroyed some Russian interests in Prague. ;-)

Of course that the anger used to have anti-Russian dimensions, too - but one should appreciate that the sentiment was mostly against the Soviet establishment as it existed at that time, not necessarily against the Russian DNA (that we partially share, anyway). By the early 1970s, the period of the so-called "Normalization" - a return to neo-Stalinist conditions and nearly complete stagnation of the economy - was firmly in place.

The occupation was suddenly referred to as "fraternal help" while the Prague Spring became a "counter-revolution attempt". This vocabulary was summarized in the "Lessons from the crisis development in the party and the society after the 13th gathering of the communist party", a propagandistic text written by the same Mr Biľak, the party's ideologue. About 300,000 people emigrated from Czechoslovakia right after 1968 and most people connected with the 1968 events were fired from jobs and schools.

For me, the occupation itself is of course just a chapter from the history textbooks and a part of my "initial conditions". I can't really blame those communist guys because if they hadn't done what they did, I wouldn't be here. Gustáv Husák, the new (Slovak) neo-Stalinist president of Czechoslovakia, established many new (not always catastrophic) policies, for example new pro-population-growth policies (support for new kids) that led to the birth of many "Husák's children" around 1974. Your humble correspondent is one of them. ;-)

Comparisons with other events

Some people compare the Warsaw Pact invasion of Czechoslovakia e.g. to the recent Russian actions in Georgia. I find such analogies kind of insulting. While I have voiced some complaints against Mr Dubček, he was an extremely peaceful guy, a naive, grown-up kid. Unlike Mr Saakashvilli, he didn't occupy Ruthenia before the invasion of our "allies". No Russian citizens were threatened anywhere in Czechoslovakia. The 1968 invasion was an action of totalitarian countries meant to destroy a newborn democracy in another country while the recent events in Caucasus are just battles between several comparably democratic countries, driven by their territorial interests. These are huge differences.


The occupation has shown that socialism has no tolerance - and cannot really have any tolerance - for internal diversity of socioeconomic systems. In some sense, the communist guys had to act if they wanted to avoid an abrupt decay of socialism in Europe (that we saw 21 years later). Socialism is an inherently totalitarian ideology. The occupation showed that it is, of course, possible to use brute force to change the fate of a country for several decades. But when the system is not built by the local people, they will never consider it their own system.

I think it is not really possible to "export" political values by force. To some extent, I think that this comment holds for the export of democracy, too. Whenever democracy started to flourish (e.g. in West Germany after the war), it was in a place that has had some experience with it.

By the way, today, in Olympic female javelin, there were only two serious contenders (besides all the amateurs): Abakumova of Russia and Špotáková of Czechia. Abakumova was ahead of Špotáková throughout the game (by 10 centimeters only). But the last throw of Špotáková changed everything: over 71 meters, Europe's new record. She earned the golden medal. She said that she was thinking about the occupation, too. So far, she is the only one who both promised and earned the gold medal. It's the third Czech gold medal and the sixth medal in total at these games. One gold medal and one silver medal was earned by Mrs Kateřina Emmons, a fellow Pilsener who married a fellow shooter from the U.S., Matt Emmons.

Wednesday, August 20, 2008 ... Deutsch/Español/Related posts from blogosphere

Strings 2008: Wednesday

You may go to the main Strings 2008 page on this blog; that page includes the live webcast

Oslo 2008, 33rd IGC: geologists are skeptical

Last week, Oslo (Norway) was hosting the 33rd International Geological Congress:

33rd IGC Oslo 2008 (main website)
They have talked about diverse topics related to geology and there are many interesting videos available on the website. But if you have 66 spare minutes (and Windows XP with Microsoft Internet Explorer), I specifically recommend you a panel discussion on climate change that took place on 08/08/08:
Panel discussion (webcast)
Henrik Svensmark and Bob Carter were on the panel and Bob Carter in particular has said many wise and nicely organized things over there. Most geologists who spoke from the audience were skeptics, too.

Tuesday, August 19, 2008 ... Deutsch/Español/Related posts from blogosphere

Strings 2008: Tuesday

First, great news from the world of awards.

Wikipedia pictures above were taken by your humble correspondent

Joe Polchinski (KITP, UCSB), Juan Maldacena (IAS Princeton), and Cumrun Vafa (Harvard University) joined other well-known physicists and won the 2008 Dirac medal for their stringy discoveries. Congratulations! But back to Strings 2008.

Monday, August 18, 2008 ... Deutsch/Español/Related posts from blogosphere

Strings 2008: Monday

...and live broadcast

Click the picture above for the Strings 2008 website. Click here for a separate window with the live webcast.

On September 10th, the video above also broadcasts the live webcast, "The First Large Hadron Collider beam", since 9:00 am Prague=CERN Summer Time (midnight Californian daylight saving time).

Climate debate: realist Monckton beats alarmist Littlemore

Start with the bottom part (1/4) to listen to this radio debate on climate change. A podcast page dedicated to the event is available, too. The debate is a full-fledged war, starting with discussions of Littlemore's blog's financial connections to organized crime.

But Roy Green, the moderator, makes it sure that they return to the climate issues (the hockey stick graph, Bangladesh, warming on other planets etc.) soon.

As expected, Christopher Monckton who is not only a skeptic but who has become quite a complete climatologist defeated Richard Littlemore, a climate alarmist who has really no idea about the issues, rather easily.

Sunday, August 17, 2008 ... Deutsch/Español/Related posts from blogosphere

LHC: panoramic pictures

Peter McCready has combined 102 high-resolution photographs of the LHC collider and its detectors into 12 amazing virtual-reality, full four-pi-steradian simulations that include some authentic sound. You can drag and move the picture and hear the natural sound, too! Flash is needed.

The complexity and the very size of this gadget - or 27 kilometers of heavy industry - may look crazy and it was rather expensive, too, especially if you realize that its only purpose is to subtly help a few hundred people similar to your humble correspondent to decide which string theory scenario is more likely. ;-)

Koutsoyiannis vs RealClimate.ORG

In this dose of peer-reviewed skeptical literature about the climate, we look to the Hydrological Science Journal. D. Koutsoyiannis, A. Efstratiadis, N. Mamassis, and A. Christofides wrote a text

On the credibility of climate predictions (PDF).
They simply compared the local predictions for temperature and precipitation by many models with the real observations and found out that:
... The results show that models perform poorly, even at a climatic (30-year) scale. Thus local model projections cannot be credible, whereas a common argument that models can perform better at larger spatial scales is unsupported.
Gavin Schmidt decided to criticize paper:
If he has an argument against the paper, I haven't found it. I agree with Schmidt's comment that it should have been expected that the models won't reproduce the local climate - even though our expectations could have very different reasons (my reason is that I simply know that the existing climate models don't properly deal with most of the essential climatological processes; I am not sure about Gavin's reasons).

The oxygen crisis

Most mainstream media have abandoned almost all quality control in their science reporting that is now arguably slightly below the image of science as presented in the leading pornographic magazines.

The latest extreme example of this observation comes from a Gentleman called Peter Tatchell, a political campaigner from the left wing of the Green party (a description that probably makes Karl Marx a staunch conservative in comparison; he's been also denounced by the British Parliament as a "homosexual terrorist" in 1994):

The Guardian, China Daily
He argues that there exists a more serious crisis than the "CO2 crisis": the oxygen levels are dropping and the human activity has decreased them by 1/3 or 1/2, he says. Wow. ;-)

The reality is, of course, that the oxygen percentage in the atmosphere has been 20.94 or 20.95 percent for thousands of years and probably much longer than that (see the historical graph on page 2 of Dudley 1998 that covers 600 million years). The amount of oxygen in the atmosphere is so huge that the biosphere (and fossil fuels which used to belong to the biosphere as well) is completely unable to change this amount significantly.

It may be useful to mention that the oxygen is only 1/5 of the atmosphere and the atmosphere is just 1/1,200,000 of the mass of the Earth. However, the Earth is damn heavy, 6 x 10^{24} kilograms, so the mass of the oxygen in the atmosphere is something like 10^{18} kilograms - about 150,000 tons per capita. Be sure that we can't burn that much oxygen even if everyone in the world were using a private jet on a daily basis. ;-) There is a simpler way to see that man-made changes to the oxygen levels are trivial and we will look at it now.

Saturday, August 16, 2008 ... Deutsch/Español/Related posts from blogosphere

Greenhouse paramilitia recommended to Australia

The director of the Australian Strategic Policy Institute, a government-funded think tank (or, more precisely, a place where all thinking tanks), and his collaborator have recommended new greenhouse brownshirts to protect Australia and the world:

Greenhouse cops needed on planetary beat
These paramilitary units, originally proposed by Tim Flannery as the global carbon regulating military junta, are required to "manage carbon markets" and these "will require compliance and enforcement".

It seems that the mad cow disease has been just transmitted to humans in Australia and the new mutated version of the disease should better be treated analogously to the original mad cow disease before it's too late. I really hope that the existing epidemiological methods and institutions and the existing police is enough to do the job.

Incidentally, some of the new cops' competencies are supposed to deal with the fraud in the market with carbon indulgences. That's surely a nice goal but we must ask: Much like in the case of the markets with human flesh, wouldn't it be a more sensible approach to start with banning these black markets?

Sweet SUSY from F-theory

The annual conference begins on Sunday (click).

In my opinion, the best hep-th paper this week was

Marsano, Saulina, Schafer-Nameki: Gauge mediation in F-theory GUT models
Even the PC people should be happy about the paper because most authors are female. ;-) (Well, except that the PC folks also dislike Russians like NS or conservatives like JM, but let me already stop here.)

They find out that the recent F-theory picture by Beasley, Heckman, Vafa (I, II) naturally realizes the "ultimate compromise" scenario for supersymmetry breaking, the sweet spot supersymmetry breaking by Ibe and Kitano (phenomenologists who may have actually predicted a real consequence of physics i.e. string theory!) that we discussed in 2007.

Spurious three-loop diagrams

Sean Carroll et al. wrote a paper - see Cosmic Variance - whose main point is to superimpose several graphs indicating the allowed strength of two particular types of dark matter interaction.

Well, my general feeling about this type of phenomenology is that the amount of work needed to draw similar conclusions is so low and the uncertainty about the relevance of different types of dark matter particles and interactions is so high that it would be a better policy not to talk about similar speculative effects in detail until there is some actual evidence - observational or theoretical - that dark matter should "work" in one way or another.

A vast majority of similar papers will be proven strictly worthless by new experiments. Sometimes it's like writing papers "10^6 should probably be greater than 10", "it should probably be greater than 20, too", "and maybe it's smaller than 20 in which case it is spectacular", and so forth. Isn't it better to calculate or measure how much 10^6 actually is?

Tabarka, Tunisia & Pilsen, Czechia

Your humble correspondent is back from Tabarka, Tunisia. What a beautiful place and weather. The sea was clean, the sky was blue, the sunscreen was badly needed on the beaches, and the temperature was 25 °C higher than what we got after we returned to a cloudy Central Europe.

While AGW hysterics like an Oliver Nutcase Tickell claim that "the idea that we could adapt to a 4 °C rise [in a few centuries] is absurd and dangerous", the Czechs not only manage to adapt to a 25 °C rise in a few hours and they enjoy it but they also pay non-trivial money for such six-times-lethal excursions. ;-)

There are thousands of Czech tourists over there at every moment of time, including at least two hotels that are entirely "Czech", with the Czech language being the 4th most important language after Arabic, French, and Italian. Too bad we haven't been a colonial power so far.

English is only powerful with important jobs such as the receptionists etc. but there's a lot of international brands written in English around. You shouldn't imagine that such countries are loaded with zealous terrorists. ;-) The economical system in Tunisia is a third-way mixture led by Ben Ali, a socialist dictator.

Because of reasons I consider confidential, we also had an authentic lunch in "our" Arab family in a nearby village.

Friday, August 15, 2008 ... Deutsch/Español/Related posts from blogosphere

Zuzana Norisová: Pátá

Original: Petula Clark: Downtown, 1964
(lyrics: go to downtown if you're feeling sad)

Source: "Rebelové" (Rebels), a Czech 2001 retro-movie

Actress/singer: Ms Zuzana Norisová (*1979), Slovakia

Friday, August 08, 2008 ... Deutsch/Español/Related posts from blogosphere

Georgia attacks South Ossetia

Previous article about a similar topic: Abkhazia

South Ossetia eventually became the first region, ahead of Abkhazia (that is of course also getting ready), where the conflict erupted a few hours ago.

The region won the independence from Georgia after the 1991-1992 War for Independence. In 2006, the de facto independent republic of South Ossetia held a referendum about the independence. 99 percent of the votes were in favor of the independence from Georgia.

Now, the Georgian government launched attacks against South Ossetia: see Google news. A few hours later, Georgia announced full military mobilization and declared a 3-hour ultimatum in which the civilians are demanded to leave their capital city.

You can see that pretty much all the events are isomorphic to the situation in Kosovo a decade ago except that the Albanians' claims for the territory of Kosovo are much weaker, both from the democratic as well as historical perspective, than the Ossetians' own claims for their independence.

Nevertheless, there exists a stunning degree of hypocrisy and double standards among most Western journalists and even the politicians. So don't expect that these folks will be celebrating the new Ossetian independence or organizing international tribunals for the Georgian aggressors.

Thursday, August 07, 2008 ... Deutsch/Español/Related posts from blogosphere

LHC will be launched on September 10th

The New York Times inform about the date. By the way, all sectors are now at 1.9 K or so except for 81 that warmed up to 3 K in average again...

Original text (August 2nd, 2008):
27 pretty hi-res LHC pictures

Photos: see Boston Globe (click!)
See also LHC panoramic pictures, LHC alarmists about the irrational hysteria, and the LHC category of articles.

All sectors except for 78 are at 1.9 K. The sector 78 is still at 4 Kelvins, too hot.

Sorry, this blog will be silent (and pre-moderated) for a week, until next Friday: vacations in North Africa. Meanwhile, have a nice time, especially the friends in the TRF community!

SoCal: global warming escalates: 433 °C

FoxNews has a very interesting "most read" story at this moment.

LA Times add a map and a video
As you know, the climate warmed up by something like 0.6 °C during the last century. But as Marx Gore and Hansen Engels warned us, the warming would escalate.

Ladies and Gentlemen, the moment is here. Places in Southern California have warmed up to 433 °C (812 °F). I am curious about your explanation - probably related to geology and volcanoes that are nearby.

The authors of 10.5 apocalypse who envisioned the continental drift to be sped up by a factor of one trillion may have underestimated Mother Nature, too! ;-)

In the poll above, dozens of people have answered that the 812 °F heat is caused by the greenhouse effect. It would be interesting to know how many of them were kidding and how many of them are true hardcore nuts who are still able to open this blog. But we will probably never know. ;-)

Dixon law firm: CyberSUSY

John Dixon from the Dixon Law Firm in Calgary submitted the first, 40-page-long preprint about CyberSUSY. He plans to write and submit four papers and they should have hundreds of pages in total.

His law firm sounds even better than a patent office and because he claims to calculate the fermion masses and solve the cosmological constant problem, among other things, I couldn't resist to look at the paper. It would be pretty easy for me to overcome all kinds of idiosyncrasies if he had something to say.

Unfortunately, five minutes is enough to transform the eager expectations into a laughter. What does he claim to do?

He claims to have a framework that breaks SUSY at the same moment when the electroweak symmetry is broken. That surely sounds impossible but you don't want to give up too early. So you read how he intends to realize such a heroic tour-de-force.

Dixon modifies the supersymmetry transformations by adding new terms that have a simple impact on some particular composite operators in the theory. After going through 10 pages, you may finally see that this is his strategy.

Cracks appear soon

However, when you want to know what exactly happens, several explosive surprises are waiting for you. First of all, the modified transformations are BRST transformations. That's not what you would expect because the BRST transformation is a technical tool to deal with local symmetries, not with global symmetries such as supersymmetry in the supersymmetric standard model.

Wednesday, August 06, 2008 ... Deutsch/Español/Related posts from blogosphere

Strominger vs Carlip and consensus scientists

Chiral gravity conjecture survives a coordinated attack of 11 wrong scientists & Strominger wins

Chiral gravity is the asymptotically AdS_3 general relativity with the usual Einstein-Hilbert term, a cosmological constant, and a (chiral) gravitational Chern-Simons term. Note that the AdS_3 isometry group is generically SO(2,2) which (locally) decomposes to SL(2,R) x SL(2,R), a group equivalent to the left-moving and right-moving symmetries in a two-dimensional conformal field theory which is the expected dual boundary CFT for all similar gravitational systems.

In January, Wei Li, Wei Song, and Andy Strominger conjectured that something special was going on for a preferred value of the cosmological constant: all the physical excitations become chiral and transform under one of the two SL(2,R) factors only.

More precisely, they showed that the chiral gravity has ghosts or negative-energy modes for generic values of the coefficients so the theory is no good but in the special case, one half of the theory completely decouples, consistency is restored, and the theory becomes chiral. A great example of a typical high-quality Strominger paper about a topic in which he is arguably the #1 leader in the world, or at least in the top 5. (And of course, Wei and Wei are great, too.)

But this conclusion had to run into all kinds of bizarre prejudices held by many people. So it has been criticized at least in 7 papers by at least 11 authors, including S. Carlip, S. Deser, A. Waldron, D.K. Wise; D. Grumiller, N. Johansson; G. Giribet, M. Kleban, M. Porrati; M.i. Park; and R. Jackiw. That's literally the world's top 11 scientists, a scientific consensus organizing a crusade against the paper by Andy, Wei, and Wei. ;-)

Information loss occurs to all orders of perturbation theory

Iizuka, Okuda, and Polchinski have confirmed something I always believed to be the case.

Hawking has shown that the information is lost in the semiclassical approximation. We know that in the full exact theory, it is preserved. But is the information lost at higher orders of the perturbative expansion?

The three authors use a matrix model to argue that the answer is almost certainly Yes, it is lost. It is a natural answer because the higher orders still respect the classical causal structure which is enough to kill the information. Another qualitative way to see the same conclusion is to notice that the phenomena that get the information outside are a form of tunneling which is a non-perturbative effect.

Their matrix model can be shown to have a discrete spectrum and to preserve the information. Nevertheless, at each order in the 1/N expansion - probably analogous to the expansion of a bulk theory in powers of Newton's constant - the information is lost and the spectrum is continuous.

The subtle difference between these two answers occurs because the long-time limit (needed to see whether the information is gone at the very end) and the large-N limit (needed to create a large black hole that may be treated by perturbative general relativity) don't commute with each other.

Tuesday, August 05, 2008 ... Deutsch/Español/Related posts from blogosphere

Tevatron falsifies Connes' model of physics

This is just way too funny and I can't resist.

Yesterday, Tevatron issued a

press release (see also Google News)
explaining that they combined the work of the two teams, CDF and D0 (a rare policy they have followed a decade ago to discover the top quark, too), and concluded that at the 95% confidence level, the Higgs mass cannot be 170 GeV.

Now, this sentence may sound very bizarre. What do they exactly mean by "170 GeV"? Do they mean the exact number? (See the picture above to appreciate the actual excluded interval: it is tiny, indeed.) A person would have to be extraordinarily hapless to predict the Higgs mass to be exactly 170 GeV, right?

MIT: cheap solar energy storage

Daniel Nocera, a condensed matter physicist from MIT, led a team that found a new, arguably cheap method to store solar energy by splitting water into oxygen and hydrogen. Links:

Popular interview (video)
More technical talk (video)
Computerworld (written story)
MIT description (written story)
Google News (list of reports)
A catalyst - cobalt metal and phosphate - creates a thin film on an electrode whenever current runs through and oxygen is produced on this film. Hydrogen must be produced on another electrode, e.g. a platinum one. Room temperature and neutral pH are enough for this "artificial photosynthesis".

The Hydrogen Scorpion, to have a cute picture here...

Well, I don't think that storage is the only problem that preserves the "alternative" status of solar energy but storage of energy in general is surely one of the problems and it is good if a better method is found. And hydrogen-based energy technologies are obviously some of the promising routes to be investigated.

Monday, August 04, 2008 ... Deutsch/Español/Related posts from blogosphere

Aleksandr Solzhenitsyn: 1918-2008

I can't write a full biography in this case. But...

Aleksandr Isayevich Solzhenitsyn died at the age of 89+. He studied mathematics in Rostov, married a chemistry student, divorced, and married a mathematician. So he was pretty close to science.

As a leading Soviet dissident, he showed the reality of Gulags to the West and won the 1970 Nobel prize for literature. America - as defined by the conservatives - liked him and viewed his message as a confirmation of Reagan's strict policies against communism.

However, the "liberals" were critical of his "reactionary" preference for Russian patriotism and the Russian Orthodox religion. He also harshly criticized what he saw as the ugliness and spiritual vapidity of the dominant pop culture of the modern West, including television and rock music: "... the human soul longs for things higher, warmer, and purer than those offered by today's mass living habits... by TV stupor and by intolerable music." He criticized consumerism, mediocracy, and the loss of traditional values.

It shouldn't be unexpected that Solzhenitsyn's relation with the "liberals" was analogous to his relation with the communists: the insulting vocabulary with words such as "reactionary" is surely not the only thing that the communists and the "liberals" (what a stupid word for freedom-haters!) share.

Also, it shouldn't be too surprising that he returned to Russia in 1990. During the last decades, he also wrote many texts revealing the overrepresentation of Jews among the revolutionaries in Russia (except for Lenin). These and other things have earned him an undeserved label of a controversial person.


Interdisciplinary trap

Gavin Schmidt and Elisabeth Moyer wrote an essay for Nature:

A new kind of scientist (click)
It almost sounds like Steve Wolfram. ;-) Schmidt talks about it at RealClimate, too. They promote "interdisciplinary" research because it is "very important" but they warn that it is "very difficult", too.

A believer prays to the Earth - oh, you're so cool - in the land of Climatia (conventionally known as Alarmistan). His female colleague looks at the ocean because it shows that the Earth and its climate are so deliciously flat; at least she thinks so. The huge continent of Skeptia (whose tiny portion was shown on the picture, for propagandistic reasons) finally sent some dragons to the totalitarian country of Alarmistan, in order to restore freedom, democracy, integrity, and common sense. Thank God. An economist is just looking at Shell.

Even though this topic has no direct relationship with the alarmism of the authors, I happen to disagree with both of their points. My attitude to the problem of "interdisciplinary" research is the following:
  • the "interdisciplinary" nature of research is mostly a cover for low-quality research; the "interdisciplinary" researchers don't have to know anything well, and whenever they're caught by the true experts, they may pretend that they know something else, too (which is usually false)
  • some gaps between the disciplines are natural and many pairs of disciplines are quasi-separated because there are not too many interesting things going on near their border
  • it is not that hard to transgress the boundaries - and many people naturally do so - but it is sensible for most researchers not to do such things because their specialization prevents them from working in other disciplines equally well
  • it would be counterproductive to artificially increase the ratio of "interdisciplinary" research; new disciplines and subdisciplines are emerging whenever some people realize that there is something interesting to investigate near the boundaries of the older disciplines
  • different disciplines have different cultures and expectations because they have been shaped by the desire to understand a particular class of phenomena; however, there only exists one kind of rational thinking; the research in every discipline (and of every single scholar) is either good or bad (or something in between) and this quality doesn't depend on any "cultures"
So let me spend some time with these points.

"Interdisciplinary" buzzwords vs quality

I don't claim that it always has to be like that. But my experience is that people usually tend to use "interdisciplinary" buzzwords if they are not good enough in the normal disciplines. I won't tell you any names but be sure that I know dozens of good examples. It is very natural for people to do such things because one of the general features of the "interdisciplinary" research is that it is not monitored too well and it usually doesn't have well-defined standards. So it is attractive for many people.

On the other hand, I know several people who are doing amazing things that could surely be classified as "interdisciplinary" if you wanted except that these people never feel the necessity to talk about it in this way. They can simply do the right things in the context of any of the "old" well-defined disciplines. For example, quantitative biology could be viewed as an emerging discipline in between biology and mathematics.

But those people who do it well can do it both in maths departments as well as biology departments. And the really good ones could do other things in one of these departments, too. They may be "multidisciplinary" rather than "interdisciplinary". There are also people in this "interdisciplinary" field who are not that good.

Gaps are natural

There is only one Universe (or, to say the least, one multiverse) and one science. But it is divided to subdisciplines. While the precise way how the disciplines were separated depends on the human culture and the historical twists and turns - and in different places, there can exist different boundaries - all these socially influenced conventions depend on some objective underlying reality, too. If there are objectively existing natural quasi-boundaries between the topics studied by two disciplines, the people who study these topics will naturally split into cultures, too.

Whether or not they feel the need to be unified depends on the amount of interactions and the exchange of information between the disciplines. Sometimes, such a flow may be very useful. Sometimes, it may be less useful. It would be absurd to say that such a flow is always useful and should universally be encouraged.

Should people transgress the boundaries?

Now, should the people be transgressing the boundaries and switch their disciplines? Obviously, some people are doing so while others are not. Should you support one group or another? The answer is, once again, No. When people switch theif fields, such an event has both advantages and disadvantages.

Among the advantages, you may see that the people bring new fresh air and ideas to the other discipline. They may help to illuminate the previously obscure questions on the boundaries of the two disciplines under consideration. The disadvantages include the need to learn completely new things. Such a need often makes a large portion of their previous education (an investment made by themselves and the society) and their work useless - a waste of time and effort.

The advantages and disadvantages are compared and they help to determine the optimum balance - the number of people who actually do such things. Attempts to inhibit or expand the process of migration would be two equally counterproductive deviations from the balance dictated by the market of ideas.

Should new disciplines be born?

Also, the world needs no one who would be creating new disciplines. Whenever an interesting body of new insights is created, it can be studied by the representatives of old disciplines for a while. Eventually, there might be reasons to transform the new subfield into a new discipline - when the required specialized knowledge becomes extensive enough for these people to fail to be experts in the original, "bigger" disciplines. Disciplines should be as large as needed for their required amount of knowledge to match what a typical researcher can learn in a reasonable timeframe.

Once again, it is a bad idea to speed up or slow down the invention and creation of new separate disciplines. There may be many regions in between the disciplines that will become hot and important fields in the future but it is unlikely that these future hot disciplines are exactly at the places where random "interdisciplinary" researchers beg for funding today. ;-)

Different cultures?

Different disciplines tend to approach their problems - and the world in general - differently. It's because different classes of questions about the world make different approaches more optimal than others. Some fields may require a high degree of mathematical rigor. Others may emphasize the depth of their understanding. Another class of disciplines may find it unimportant for the deep explanations to be found and its members are satisfied as soon as they know the correct answers. One discipline may expect the numbers to be very accurate. Another discipline is satisfied with a lower accuracy.

One discipline may build on very complicated models and another discipline prefers robust models with a small number of wheels and gears. Whenever the scientists in the disciplines behave rationally, all these differences between the cultures reflect genuine and objective differences between the topics studied by these disciplines. Different topics make different strategies more promising - even though some narrow-minded simpletons are unable to realize this fact. But if there are significant differences that arise purely due to the "culture", not due to the objective causes, you can be sure that at least one of these "cultures" is behaving suboptimally.

Climate vs economics

Schmidt and Moyer argue that the climate models are much more complicated than the models in economics. The economics models look rudimentary to the climatologists while the climate models look like Rube Goldberg machines to the economists, they say.

Is it true? Is it justified? It is good? Is it bad? Well, I think it is true to some extent. But such differences can only partially be justified by the real differences between the discipilines which means that the differences reveal that at least one of the disciplines is doing something wrong. What do I mean?

Many climatologists believe that they know all the crucial physical phenomena that govern the climate and they can properly combine them into the models. Because the climate is a pretty complex system, the models will be pretty complicated. They may reflect many complexities of the 3+1-dimensional setup.

Economists tend to think that the relationships between many observables are badly understood. Their field is about the human behavior, after all. Human behavior is more complex and less predictable than physics, isn't it? So economists tend to use models with a limited number of observables.

The two previous paragraphs could explain why the climatologists tend to invent more convoluted models than the economists. But does this explanation of the difference also fully justify the different strategies? Well, not really.

When you try to decide about the optimum complexity of your model to learn something new about the system you study, what should matter are not your pre-determined, a priori opinions how much you want to include and how many effects you have heard about. Instead, you should look at the a posteriori results of the models with one degree of complexity or another. How many correct things are you actually learning by writing one model or another?

Are the models' complexities justified?

The thing that matters is the actual ability of the complicated models to reproduce the features of reality that a discipline wants to master.

In high-energy physics, you clearly need rather complex "models" - nothing easier than quantum field theories and/or string theory is enough to understand the phenomena that we can actually comprehend and predict today. They (quantum field theories etc.) are complex for the laymen but the experts know that in their essence, these models are actually extraordinarily robust and they don't have too many independent assumptions, parameters, or basic concepts, especially if you compare them e.g. with climate models (and string theory is even more robust, in this sense, even though this fundamental point is completely inpenetrable for 99.9% of the public). But what about climatology and economics?

I am convinced that if you look at the typical accuracy and predictability of phenomena in climatology and economics, you will see that they are fully comparable. Both of these disciplines work with a lot of chaotic functions of time, complex systems influenced by thousands of effects. And both of them end up with predictions that differ from reality by something comparable to 10-100% or more. ;-)

In my opinion, this fact - the actual ability to tell you useful and true things about the world - should decide about the optimal complexity of the models you use. And it is the economists who are approaching these problems more sensibly, by paying some attention to Occam's razor. If more detailed models with many new independent wheels and gears don't allow you to make more detailed and accurate predictions that can be verified than the older and simpler ones, there is no rational reasons to add these wheel and gears.

Economists don't add them unless they're forced to. Climatologists often add these features even though they are not tested and they don't play any demonstrably good role for their understanding of the actual physical system, the climate. Nevertheless, they seem to be proud about the complexity, whether or not this complexity teaches us something about the real world.

What is needed to fix this situation are not "interdisciplinary" researchers but rather climatologists who have sane ideas and a lot of expertise about the wheels and gears that have actually been validated. And those who know how to repair them or replace them whenever it is needed. To summarize, I think that what climate science and other sciences need are not researchers who are more "interdisciplinary" or a "new kind of scientists" but researchers who are more "good" in their job which should be the "old kind of science", not a new one.

And that's the memo.

Bonus: records of the day

The monthly average Sunspot number for June 2008 was 0.5, the lowest figure since June 1954. Also, Anthony Watts points out that the January-July increment of Mauna Loa CO2 reading was negative in 2008, for the first time in recorded history. Someone apparently began to suck CO2. ;-) (Update: it was of course an error in the data that was later corrected.)

(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','//','ga'); ga('create', 'UA-1828728-1', 'auto'); ga('send', 'pageview');