Testing E=mc2 for centuries

Chad Orzel seems to disagree with my comments about the interplay between the theory and experiment in physics. That's too bad because I am convinced that a person who has at least a rudimentary knowledge about the meaning, the purpose, and the inner workings of physics should not find anything controversial in my text at all.

Orzel's text is titled "Why I could never be a string theorist" but it could also be named "Why I could never be a theorist or something else that requires to use the brain for extended periods of time". Note that the apparently controversial theory won't be string theory; it will be special relativity. The critics who can't swallow string theory always have other, much older and well-established theories that they can't swallow either.

The previous text about the theory vs. experiment relations

Recall that I was explaining a trivial fact that in science in general and physics in particular, we can predict the results of zillions of experiments without actually doing them. It's because we know general enough theories - that have been found by combining the results of the experiments in the past with a great deal of theoretical reasoning - and we know their range of validity and their accuracy. And a doable experiment of a particular kind usually fits into a class of experiments whose results are trivially known and included in these theories. This is what we mean by saying that these are the correct theories for a given class of phenomena. An experiment with a generic design is extremely unlikely to be able to push the boundaries of our knowledge.

When we want to find completely new effects in various fields, we must be either pretty smart (and lucky) or we must have very powerful apparata. For example, in high-energy physics, it's necessary that we either construct accelerators that accelerate particles to high energies above 100 GeV or so - this is why we call the field high-energy physics - or we must look for some very weak new forces, for example modifications of gravity at submillimeter experiments, or new, very weakly interacting particles. (Or some new subtle observations in our telescopes.)

If someone found a different, cheaper way to reveal new physics, that would be incredible; but it would be completely foolish to expect new physics to be discovered in a generic cheap experiment.

Random experiments don't teach us anything

It's all but guaranteed that if we construct a new low-energy experiment with the same particles that have been observed in thousands of other experiments and described by shockingly successful theories, we are extremely unlikely to learn anything new. This is wasting of taxpayers' money especially if the experiments are very expensive.

In the particular case of the recent "E=mc^2 tests", the accuracy was "10^{-7}" while we know experimentally that the relativistic relations are accurate with the accuracy "10^{-10}", see Alan Kostelecky's website for more concrete details. We just know that we can't observe new physics by this experiment.

Good vs. less good experiments

In other fields of experimental physics, there are other rules - but it is still true that one must design a smart enough experiment to be able to see something new or to be able to measure various things (or confirm the known physical laws) with a better accuracy than the previous physicists. There are good experimentalists and less-good experimentalists (and interesting and not-so-interesting experiments) which is the basic hidden observation of mine that apparently drives Ms. or Mr. Orzel up the wall.

Once again: What I am saying here is not just a theorist's attitude. Of course that it is also the attitude of all good experimentalists. It is very important for an experimentalist to choose the right doable experiments where something interesting and/or new may be discovered (or invented) with a nonzero probabilitity. There is still a very large difference between the experiments that reveal interesting results or inspire new ideas and experiments that no one else finds interesting.

Every good experimentalist would subscribe to the main thesis that experiments may be more or less useful, believe me. Then there are experimentalists without adjectives who want to be worshipped just for being experimentalists and who disagree with my comments; you may guess what is the reason.

Of course that one may design hundreds of experiments that are just stamp-collecting - or solving a homework problem for your experimental course. I am extremely far from thinking that this is the case everywhere outside high-energy physics. There have been hundreds of absolutely fabulous experiments done in all branches of physics and dozens of such experiments are performed every week. But there have also been thousands of rather useless experiments done in all these fields. Too bad if Ms. or Mr. Orzel finds it irritating - but it is definitely not true that all experiments are created equal.

Interpreting the results

Another issue is that if something unexpected occured in the experiment that was "testing E=mc^2", the interpretation would have to be completely different than the statement that "E=mc^2" has been falsified. It is a crackpot idea to imagine that one invents something - or does an experiment with an iron nucleus or a bowl of soup - that will show that Einstein was stupid and his very basic principles and insights are completely wrong.

Hypothetical deviations from the Lorentz invariance are described by terms in our effective theories. Every good experimentalist first tries to figure out which of them she really measures. Neither of these potential deviations deserves the name "modification of the mass-energy relation" because even the Lorentz-breaking theories respect the fact that since 1905, we know that there only exists one conserved quantity to talk about - mass/energy - that can have various forms. We will never return to the previous situation in which the mass and energy were thought to be independent. It's just not possible. We know that one can transform energy into particles and vice versa. We can never unlearn this insight.

New physics vs. crackpots' battles against Einstein

Einstein was not so stupid and the principles of his theories have been well-tested. (The two parts of the previous sentence are not equivalent but they are positively correlated.) To go beyond Einstein means to know where is the room for any improvement, clarification, or deformation of his theories and for new physics, and the room is simply not in the space of ideas that "E=mc^2 is wrong" or "relativity is flawed". A good experimentalist must know something about the theory, to avoid testing his own laymen's preconceptions about physics that have nothing to do with the currently open questions in physics.

Whether or not an experimental physicist likes it or not, we know certain facts about the possible and impossible extensions and variations of the current theories - and a new law that "E=mc^2" will be suddenly violated by one part in ten million in a specific experiment with a nucleus is simply not the kind of modification that can be done with the physical laws as we know them. Anyone who has learned the current status of physics knows that this is not how serious 21st century physics looks like. The current science is not about disproving some dogmatic interpretations of Bohr's complementarity principle either.

Chad Orzel is not the only one who completely misunderstands these basic facts. Hektor Bim writes:

• Yeah, this post from Lubos blew me away, and I’ve been trained as a theorist.

Well, it does not look like a too well-trained one.

• As long as we are still doing physics (and not mathematics), experiment rules.

Experiments may rule, but there are still reasonable (and even exciting) experiments and useless (and even stupid) experiments. If someone thinks that the "leading role" of the experiments means that the experimentalists' often incoherent ideas about physics are gonna replace the existing theories of physics and that every experiment will be applauded even if it is silly, is profoundly confused. Weak ideas will remain weak ideas regardless of the "leading role" of the experiments.

• What also blew me away is that Lubos said that “There is just no way how we could design a theory in which the results will be different.” This is frankly incredible. There are an infinite number of ways that we could design the theory to take into account that the results would be different.

Once again, there are no ways how to design a scientific theory that agrees with the other known experiments but that would predict a different result of this particular experiment. If you have a theory that agrees with the experiments in the accelerators but gives completely new physics for the iron nucleus, you may try to publish it - but don't be surprised if you're described as a cook.

Of course that crackpots always see millions - and the most spectacular among them infinitely many ;-) - ways to construct their theories. The more ignorant they are about the workings of Nature, the more ways to construct the theories of the real world they see. The most sane ones only think that it is easy to construct a quantum theory of gravity using the first idea that comes to your mind; the least sane ones work on their perpetuum mobile machines.

I only mentioned those whose irrationality may be found on the real axis. If we also included the cardinal numbers as a possible value of irrationality, a discussion of postmodern lit crits would be necessary.

Scientific theories vs. crackpots' fantasies

Of course someone could construct a "theory" in which relativity including "E=mc^2" is broken whenever the iron nuclei are observed in the state of Massachusetts - much like we can construct a "theory" in which the law of gravity is revoked whenever Jesus Christ is walking on the ocean. But these are not scientific theories. They're unjustifiable stupidities.

The interaction between the theory and experiments goes in both ways

It is extremely important for an experimental physicist to have a general education as well as feedback from the theorists to choose the right (and nontrivial) things to measure and to know what to expect. It is exactly as important as it is for a theorist to know the results of the relevant experiments.

Another anonymous poster writes:

• What Lumo seems to argue is that somehow we can figure out world just by thinking about it. This is an extremely arrogant and short-sighted point of view, IMPO – and is precisely what got early 20th century philosophers in trouble.

What I argue is that it is completely necessary for us to be thinking about the world when we construct our explanations of the real world as well as whenever we design our experiments. And thinking itself is responsible at least for one half of the big breakthroughs in the history of science. For example, Einstein had deduced both special relativity as well as general relativity more or less by pure thought, using only very general and rudimentary features of Nature known partially from the experiments - but much more deeply and reliably from the previous theories themselves. (We will discuss Einstein below.)

Thinking is what the life of a theoretical physicist is mostly about - and this fact holds not only for theoretical physicists but also other professions including many seemingly non-theoretical ones. If an undereducated person finds this fact about the real world "arrogant", it is his personal psychological problem that does not change the fact that thinking and logical consistency are among the values that matter most whenever physical theories of the real world are deduced and constructed.

The anonymous poster continues:

• By the same reasoning the orbits of the planets must be circular – which is what early “philosophers” argued at some point.

Circular orbits were an extremely useful approximation to start to develop astrophysics. We have gone through many other approximations and improvements, and we have also learned how to figure out which approximations may be modified and which cannot. Cutting-edge physics today studies neither circular orbits nor the questions whether "E=mc^2" is wrong; it studies very different questions because we know the answers to the questions I mentioned.

Pure thought in the past and present

A wise physicist in 2005 respects the early scientists and philosophers for what they have done in the cultural context that was less scientifically clear than the present era, but she clearly realizes their limitations and knows much more than those early philosophers. On the other hand, a bad and arrogant scientist in 2005 humiliates the heroes of the ancient science although he is much more dumb than they were, and he is asking much more stupid questions and promoting a much more rationally unjustifiable criticism of science in general than the comparably naive early philosophers could have dreamed about.

Of course that in principle, one can get extremely far by pure thought, if the thought is logically coherent and based on the right principles, and many great people in the history of science indeed had gotten very far. These are the guys whom we try to follow, and the fact that there have been people who got nowhere by thinking cannot change the general strategy either.

• Anthropic principle completely destroys whatever is left of the “elegance” argument, which is why it’s entertaining to see what will happen next.

I know that some anti-scientific activists would like to destroy not only the "elegance" of science but the whole science - and join forces with the anthropic principle or anything else if necessary - but that does not yet mean that their struggle has any chance to succeed or that we should dedicate them more than this single paragraph.

Another anonymous user writes:

• As far as what Lubos meant, only he can answer that. But it would be obviously foolish to claim relativity could have been deduced without experimental input, and Lubos, whatever else he might be, is no fool.

History of relativity as a victory of pure thought

If interpreted properly, it would not be foolish; it is a historical fact. For example, I recommend you The Elegant Universe by Brian Greene, Chapter 2, for a basic description of the situation. Einstein only needed a very elementary input from the experiments - namely the invariance of physical laws under uniform motion; and the constancy of speed of light - which naturally follows from Maxwell's equations and Einstein was sure that the constancy was right long before the experiments showed that the aether wind did not exist.

It is known pretty well that the Michelson-Morley experiments played a rather small role for Einstein, and for some time, it was even disputed whether Einstein knew these experiments at all back in 1905. (Yes, he did.) Some historians argue that the patented ideas about the train synchronization themselves played a more crucial role. I don't believe this either - but the small influence of the aether wind experiments on Einstein's thinking seems to be a consensus of the historians of science.

Einstein had deeply theoretical reasons to be convinced about both of these two assumptions. Symmetry such as the Galilean/Lorentz symmetry or "the unity of physical explanations" are not just about some irrelevant or subjective concepts of "beauty". They are criteria that a good physicist knows how to use when he or she looks for better theories. The observation that the world is based on more concise and unified principles than what the crackpots and laymen would generally expect is an experimentally verified fact.

These two observations are called the postulates of special relativity, and the whole structure of special relativity with all of its far-reaching consequences such as the equivalence of matter and energy follows logically. Needless to say, all of these effects have always been confirmed - with accuracy that currently exceeds the accuracy available to the experimentalists of Einstein's era by very many orders of magnitude. Special relativity is a genuine and true constraint on any theory describing non-gravitational phenomena in our Universe, and it is a strong constraint, indeed.

Importance of relativity

Whoever thinks that it is not too important and a new experiment with a low-energy nucleus may easily show that these principles are wrong, which essentially allows us to ignore special relativity, and that everything goes after all, is a crackpot.

General relativity: even purer thought

In a similar way, the whole structure of general relativity was derived by the same Einstein purely by knowing the previous special theory of relativity plus Newton's approximate law of gravity, including the equivalence of the inertial and gravitational mass; the latter laws were 250 years old. There was essentially no room for experiments. The first experiments came years after GR was finished, and they always confirmed Einstein's predictions.

The known precession of Mercury's perihelion is an exception; this prediction of GR was known before Einstein, but Einstein only calculated the precession after he had completed his GR, and henceforth, the precession could not directly influence his construction of GR. He was much more influenced and impressed by Ernst Mach, an Austrian philosopher. I don't intend to promote Mach - but my point definitely is to show that the contemporary experiments played a very small role when both theories of relativity were being developed.

There were also some experiments that argued that they rejected the theory, and Einstein knew that these experiments had to be wrong because "God was subtle but not malicious". Of course that Einstein was right and the experiments were wrong. (Similar stories happened to many great theoretical physicists; an experiment of renowned experimentalists that claimed to have falsified Feynman-Gell-Mann's theory of V-A interactions was another example - and Feynman knew right away when he was reading the paper that the experimentalists were just being silly.) Our certainty today that special relativity (or the V-A nature of the weak interactions) is correct in the "simply doable" experiments is much higher than our confidence in any single particular experimentalist. You may be sad or irritated, but that's about everything that you can do against this fact.

Other theories needed more experiments

It would be much harder to get that far without experiments in quantum mechanics and particle physics, among many other branches of physics and science, but whoever questions the fact that there are extremely important insights and principles that have been found - and/or could be found or can be found - by "pure thought" (or that were correctly predicted long before they were observed), is simply missing some basic knowledge about science.

Although I happily admit that we could not have gotten that far without many skillful (and lucky) experimentalists and their experiments, there have been many other examples beyond relativity in which important theories and frameworks were developed by pure mathematical thinking whose details were independent of experiments. The list includes, among hundreds of other examples,

• Dirac's equation. Dirac had to reconcile the first-order Schrödinger equation with special relativity. As a by-product, he also predicted something completely unknown to the experimentalists, namely antiparticles. Every successful prediction may be counted as an example of theoretical work that was not driven by experiments.
• Feynman's diagrams and path integral. No one ever really observed "diagrams" or "multiple trajectories simultaneously contributing to an experiment". Feynman appreciated Dirac's theoretical argument that the classical concept of the action (and the Lagrangian) should play a role in quantum mechanics, too, and he logically deduced that it must play role because of his sum over trajectories. The whole Feynman diagram calculus for QED (generalizable to all other QFTs) followed by pure thought. Today we often say that an experiment "observes" a Feynman diagram but you should not forget about the huge amount of pure thought that was necessary for such a sentence to make any sense.
• Supersymmetry and string theory. I won't provoke the readers with a description.

Lorentz violations are not too interesting and they probably don't exist

• If he is claiming that Lorentz invariance must be exact at all scales, then I agree that he’s being ridiculous. But I think it is reasonable to claim that this experiment was not really testing Lorentz invariance at a level where it has not been tested before.

What I am saying is that it is a misguided approach to science to think that the next big goal of physics is to find deviations from the Lorentz invariance. We won't find any deviations. Most likely, there aren't any. The hypotheses about them are not too interesting. They are not justified. They don't solve any puzzles. Even if we find the deviations and write down the corresponding corrections to our actions, we will probably not be able to deduce any deep idea from these effects. Since 1905 (or maybe the 17th century), we know that the Lorentz symmetry is as fundamental, important and natural as the rotational symmetry.

The Lorentz violation is just one of many hypothetical phenomenological possibilities that can in principle be observed, but that will probably never be observed. I find it entertaining that those folks criticize me for underestimating the value of the experiments when I declare that the Lorentz symmetry is a fundamental property of the Universe that holds whenever the space is sufficiently flat. Why is it entertaining? Because my statement is supported by millions of accurate experiments while their speculation is supported by 0.0001 of a sh*t. It looks like someone is counting negative experiments as evidence that more such experiments are needed.

The only reason why the Lorentz symmetry irritates so many more people than the rotational symmetry is that these people misunderstand 20th century physics. From a more enlightened perspective, the search for the Lorentz breaking is equally (un)justified as a search for the violation of the rotational symmetry. The latter has virtually no support because people find the rotational symmetry "natural" - but this difference between rotations and boosts is completely irrational as we have known since 1905.

Parameterizing Lorentz violation

In the context of gravity, the deviations from the Lorentz symmetry that can exist can be described as spontaneous symmetry breaking, and they always include considering the effect of gravity as in general relativity and/or the presence of matter in the background. In the non-gravitational context, these violations may be described by various effective Lorentz-breaking terms, and all of their coefficients are known to be zero with a high and ever growing degree of accuracy. Look at the papers by Glashow and Coleman, among others.

Undoing science?

The idea that we should "undo" the Lorentz invariance, "undo" the energy-mass equivalence, or anything like that is simply an idea to return physics 100 years into the past. It is crackpotism - and a physics counterpart of creationism. The experiments that could have been interesting in 1905 are usually no longer so interesting in 2005 because many questions have been settled and many formerly "natural" and "plausible" modifications are no longer "natural" or "plausible". The previous sentence comparing 1905 and 2005 would be obvious to everyone if it were about computer science - but in the case of physics, it is not obvious to many people simply because physics is harder to understand for the general public.

But believe me, even physics has evolved since 1905, and we are solving different questions. The most interesting developments as of 2005 (for readers outside the Americas: 2006) are focusing on significantly different issues, and whoever describes low-energy experiments designed to find "10^{-7}" deviations from "E=mc^2" as one of the hottest questions in 2005 is either a liar or an ignorant. It is very fine if someone is doing technologically cute experiments; but their meaning and importance should not be misinterpreted.

Internet gender gap

First, an off-topic answer. Celal asks me about the leap seconds - why has not the Earth already stopped to rotate if there are so many leap seconds. The answer is that we are now indeed inserting a leap second in most of the years - which means that one year is longer by roughly 1 second than it was back in 1820 when the second was defined accurately enough. More precisely, what I want to say is that one solar day is now longer by roughly 1/365 of a second than it was in the 19th century; what matters is of course that the noon stays at 12 pm.

Although the process of slowing down the Earth's rotation has some irregularities, you can see that you need roughly 200 years to increase the number of the required leap seconds per year by one. In order to halve the angular velocity, you need to increase the number of leap seconds roughly by 30 million (the number of seconds per year), which means that you need 30 million times 200 years which is about 6 billion years. Indeed, at time scales comparable to the lifetime of the solar system, the length of the day may change by as much as 100 percent.

100 percent is a bit of exaggeration because a part of the recent slowing is due to natural periodic fluctuations and aperiodic noise, not a trend. However, coral reefs indeed seem to suggest that there were about 400 days per year 0.4 billion years ago. Don't forget that the slowing down is exponential, I think, and therefore the angular velocity will never quite drop to zero (which has almost happened to our Moon).

BBC informs that

• gender gap is alive and well online.

While the same percentage of men and women use the internet, they use it in very different ways & they search for very different things. Women focus on maintaining human contacts by e-mail etc. while men look for new technologies and ways to do new things in novel ways.

• "This moment in internet history will be gone in a blink," said Deborah Fallows, senior research fellow at Pew who wrote the report.

I just can't believe that someone who is doing similar research is simultaneously able to share such feminist misconceptions. The Internet has been around for ten years and there has never been any political or legal pressure for the men and women to do different things - the kind of pressures in the past that is often used to justify similar hypotheses about the social origin of various effects.

People are just doing whatever they find natural to do with the internet, and a result is that there are significant differences between men and women. These differences follow primarily from the fact that we are wired differently. Everyone who is able to look around and evaluate the perceptions knows that.

Growing gender gap in computer science

Meanwhile, the gender gap grows in computer science (CS). Boston Globe describes the computer science department of Tufts University. Twenty years ago, many women were attracted to the department in order for the social engineers to produce "gender equality". The peak of this movement was in 1985 when as many as 37 percent of the computer science Bc. degrees went to women.

You have had everything you need according to the pseudoscientific theories of discrimination: a lot of female role models and good, welcoming atmosphere. Nevertheless, the airplanes don't land. The percentage of women among the new alumni dropped below 20 percent again. Something must be wrong, right? Still, many people are going to continue to propagate their patently false explanations of the observed statistics that have been falsified hundreds of times. For example, the Boston Globe article by Marcella B. wrote

• As the popularity of computer science soared in the first half of the 1980s, many university departments became overburdened and more competitive, some professors argue. Introductory classes were taught in a way that emphasized technical minutiae over a broader sense of what was important and exciting about the field, a style catering to the diehard -- and overwhelmingly male -- techies rather than curious new recruits.

This is a completely unreasonable comment. The reality is that the field of computer science simply is a competitive field. It has been one for quite many years. And the males seem to be doing statistically better both in the technical minutiae of that field as well as in the excitement about its general features. Moreover, both of these things - general excitement as well as technical details - are necessary for the computer science people to do their work competitively. Abandoning "technical minutiae" is nothing else than lowering the standards.

I wonder how many more years, decades or centuries are necessary for the believers in various feminist religions to start to realize that something is wrong with their beliefs.

Next target of terrorists: Indian string theorists

A newspaper in Bombay informs that

• Bangalore attack faces retaliation in blogosphere

The terror attack at the Indian Institute of Science campus in Bangalore on Wednesday that killed a retired IIT professor has sent shockwaves through the Indian blogosphere.

Blogger and researcher, Kate, wondered if Tata Institute of Fundamental Research [the prominent Indian center of string theory] would be the next target.

...

Rashmi Bansal expressed sadness at scientists becoming the latest terror victims. “I mean, sure, there would be some routine security checks at the gate, but who seriously believes that a bunch of scientists gathered to discuss string theory or particle physics could be of interest to the Lashkar-e-Toiba?” she wrote in her blog, Youth Curry (http://youthcurry.blogspot.com/).

Ms. Bansal may change her mind if she analyzed some posters here - to see at least a "demo" how the anger against the values of modern science can look like. More generally, I emphasize that my warning is absolutely serious. It is not a joke, and I've erased a misleading anonymous comment that suggested that.

Finally, I think that whoever thinks that a scientist cannot become a victim of terrorists is plain stupid. The islamic extremists fight against the whole modern civilization, and the string theorists in India and elsewhere - much like the information technologies experts - are textbook examples of the infiltration of the modern civilization and, indeed, the influence of the Western values - or at least something that was associated with the Western values at least for 500 years.

Everyone who observes the situation and who is able to think must know that Bangalore has been on the terrorists' hit list for quite a while.

If the person who signed as "Indian physicist" does not realize that and if he or she were hoping that the terrorists would treat him or her as a friend (probably because they have the same opinions about George W. Bush?), I recommend him or her to change the field because the hopes were completely absurd.

I give my deepest condolences to the victim's family but I am not gonna dedicate special sorrow to the victim, Prof. Puri, just because he was a retired professor. There are many other innocent people being killed by the terrorists and I am equally sad for all of them. The death of the innocent people associated with "our" society is of course the main reason why I support the war on terror - or at least its general principles. The attack against the conference is bad, but for me it is no surprise. And the casualties of 9/11 were 3,000 times higher which should still have a certain impact on the scale of our reactions.

Third string revolution predicted for physics

CapitalistImperialistPig has predicted

• a third superstring revolution

for 2006, started by someone who is quite unexpected. It would be even better if the revolution appeared in the first paper of the year.

Sidney Coleman Open Source Project

Jason Douglas Brown has been thinking about a project to transcribe the QFT notes of a great teacher into a usable open source book. I am going to use the notes in my course QFT I in Fall 2006; see the Course-notes directory.

We are talking about 500 pages and about 10 people who would share the job. If you want to tell Jason that it is a bad or good idea, or join his team, send an e-mail to

• jdbrown371 at hisurfer.net

Bayesian probability I

See also a positive article about Bayesian inference...

Two days ago, we had interesting discussions about "physical" situations where even the probabilities are unknown.

Reliable quantitative values of probabilities can only be measured by the same experiment repeated many times. The measured probability is then "n/N" where "n" counts the "successful measurements" among all experiments of a certain kind whose total number is "N". This approach defines the "frequentist probability", and whenever we know the correct physical laws, we may also predict these probabilities. If you know the "mechanism" of any system in nature - which includes well-defined and calculable probabilities for all well-defined questions - you can always treat the system rationally.

Unknown probabilities

It is much more difficult when you are making bets about some events whose exact probabilities are unknown. Even in these cases, we often like to say a number that expresses our beliefs quantitatively. Such a notion of probability is called Bayesian probability and it does not really belong to exact sciences.

Vendor machines

For example, you pay three quarters to a vendor machine to get Coke for 1 dollar. The third quarter is swallowed but not counted. Should you try to throw two (or more) quarters to the same vendor machine, or should you rather choose the next machine which is more likely (and let's assume that it is guaranteed) to work correctly but where you will have to pay 4 more coins?

If you knew the probability that the first machine is gonna steal your coins - for example, imagine that someone told you that the machine steals every coin with probability P, independently of others - you could solve this problem mathematically and calculate which strategy has a lower expectation value of the money that you will have to pay in total.

However, you don't know P. Because the machine has stolen one quarter among three, you may think that the probability of a "theft" is around 1/3. With the number P=1/3, you may again derive the correct answer. (In fact, taking the risk and continuing with the unreliable machine is cheaper in average.)

But if you were just "lucky" that only one coin was stolen, the probability that the machine will steal your money can be close to one. In this case, abandoning this machine is clearly cheaper. An important conclusion is that there is no canonical way to determine the probability that the "theft rate" of the vendor machine is between P and P+dP. (I used the words "theft rate" because once you interpret this observable as a permanent characteristic of the machine, it is no longer a probabilistic observable.)

Imagining the distribution for the theft rate

You may imagine that the distribution of P is Gaussian, with a center around 1/3 and with width determined by the fact that you have only made 3 measurements. But it is very important how this distribution behaves near P=1. If it were non-zero near P=1 (like the Gaussian), the expected average value of the coins you will have to pay would actually be logarithmically divergent.

You actually know that P cannot be one because two coins have been counted correctly. But even if the probability distribution goes to zero near P=1, but just terribly quickly (so that it is pretty big even if you're very close to P=1), you may still obtain a divergence.

This is where rational thinking ends and religion starts. You simply can't know whether these extremely unlikely events are just very unlikely or absurdly unlikely. And depending on the probability that the theft rate is close to one, you will obtain different conclusions about the optimal strategy.

Insurance and averaging

Whenever we talk about phenomena that occur many times and whose losses as well as benefits are "minor" relatively to what we can afford, the expectation values are the only truly "rational" measurement of the quality of different decisions. For example, a billionaire would be stupid to buy all tickets in the lottery because he knows that 15 percent of his payment (or another percentage that can be calculated almost exactly) would go to the company that runs the lottery.

Such a billionaire would be stupid but he would still be incredibly less stupid than a country that codifies the Kyoto protocol.

In a similar way, a millionaire does not need an insurance against many "minor" things because even in this case, he can calculate pretty accurately what percentage of his payment will be swallowed by the insurance company. On the other hand, a millionaire can also afford to pay the insurance even if it statistically means a loss for him. Millionaires can afford to behave irrationally, in all possible directions.

Huge lotteries and critical insurance

But when you are thinking about the insurance against an event whose impact would be devastating - or if you are thinking about a lottery where you can win large amounts of money that can "solve everything" - it is clear that the rational thinking and expectation values become less important.

Similar issues were relevant when we were thinking about "betting on the climate" and the two sides had vastly different ideas what are the probabilities of different events. One party thought that the probabilities were 50:50 while the other party thought it was closer to 99:1. In this case, once again, we don't know what is the true probability. Any assumption in between these two is statistically attractive for both parties. I mentioned that the geometric average of the two ratios - close to 90:10 - looks as the fairest assumption but there is no way to justify this convention or other conventions simply because the true probability is unknown.

Once you agree about the probability, the rules for your bet are, of course, defined by requiring that the statistical average of the amount of money that is won/lost by either party is zero.

Also, when we predict the death of the Universe or any other event that will only occur once, we are outside science as far as the experimental tests go. We won't have a large enough dataset to make quantitative conclusions. The only requirement that the experiment puts on our theories is that the currently observed reality should not be extremely unlikely according to the theory. For example, the lifetime of our Universe should never be predicted to be much smaller than 14 billion years because it would be surprising to see that we are still here.

Which probabilities are scientific

While the text above makes it clear that I only consider the frequentist probabilities to be a subject of the scientific method including all of its sub-methods, it is equally clear that perfect enough theories may allow us to predict the probabilities whose values cannot be measured too accurately (or cannot be measured at all) by experiments. It is no contradiction. Such predictions are still "scientific predictions" but they cannot really be "scientifically verified". Only some features of the scientific method apply in such cases.

All stem cell lines were fabricated

All - not just nine - of Hwang Woo-Suk's eleven stem cell lines were fabricated, a panel of Seoul National University concluded today.

• CTV.CA reports

It is still plausible that Hwang's team has successfully cloned a human embryo and the Afghan hound. And Hwang still claims to have developed a technology to build the stem cell lines although he is no longer a trustworthy source. However, the apparent failure to have actually produced the patient-specific stem cell lines implies that a realistic application of these biotechnologies in medicine may be decades (or infinitely far) away.

Moreover, the Washington Post claims that the Korean government has probably bribed some scientists - potential whistleblowers - in order to protect the non-existent good name of Korean biology in the international context.

Some people argue that the whole science will suffer as a consequence of this scandal. I don't buy these worries. If someone criticizes the work of the Korean scientists; as well as the work of their colleagues everywhere in the world who could not figure out what was going on; as well as the work of the journalists who inflated this research into a sensation; as well as the editors of the journals and the Korean government officials who have paid a lot of money without proper checks and balances - I am convinced that at least 90% of this criticism is justified.

People will keep on trying to develop these technologies that could be used to cure many diseases because the potential benefits are huge. They will do so in many countries (and many states) that don't ban this research. I am not afraid that the research will collapse. And the scientists will no longer be viewed as innocent angels. This is very correct. The scientists may be smart and they can work a lot, but they can still share vices with ordinary, mortal human beings. The real science and the ideal science are two different things. For example, many colleagues of ours care about the money far too much. Hwang et al. received 60 million dollars or so. This is not a formality. Many of us would be, unfortunately, ready to improve the results in order to get this money.

It is very important to know that an article published in Science or Nature does not have to be correct. A scientist identified as a top scientist by the Scientific American may be a bubble of fraud. Whenever there is a lot of money at stake, the probability that something is fraud increases. The fields with huge potential applications - in medicine or politics of "climate change" - are the first ones where fraud should be expected and where efficient mechanisms to prevent such fraud should be developed.

Recall that in November, we discussed why Most published findings are false. It was explained that a paper is more likely to be wrong if the field is hot, if the financial stakes are high, if the sample size is small, and if a small fraction of relationships is tested. Hwang's research fits into a large portion of these criteria - so it should have been expected that it was not right.

The work of reviewers is usually not paid at all and it turned out to be quite inefficient in dividing good stuff from bad stuff. Maybe these guys eventually find out that submitting their work to the arXiv is as good as publishing things in Nature and Science. However, new policies to avoid similar fraudulent research in the future will be required, I think.

Wikipedia

Comment about the new colors: I believe that the new colors are not a registered trademark of Paul Ginsparg. Moreover, mine are better.

Just a short comment about this creation of Jimbo Wales et al. I am impressed how unexpectedly efficient Wikipedia is. Virtually all of its entries can be edited by anyone in the world, even without any kind of registration. When you realize that there are billions of not-so-smart people and hundreds of millions of active idiots living on this blue planet - and many of them have an internet access - it is remarkable that Wikipedia's quality matches that of Britannica.

But this kind of hypertext source of knowledge is exactly what the web was originally invented for.

Moreover I am sure that Wikipedia covers many fields much more thoroughly than Britannica - and theoretical physics may be just another example. Start with list of string theory topics, 2000+ of my contributions, or any other starting point you like. Try to look for the Landau pole, topological string theory, heterotic string, or thousands of other articles that volunteers helped to create and improve. Are you unsatisfied with some of these pages? You can always edit them.

You may also try to search for your name. Chances are that your page, perhaps including a photograph, has been added by your humble correspondent. For example, are you Lenny Susskind, Joe Polchinski, Cumrun Vafa, Nima Arkani-Hamed, Andrew Strominger, Juan Maldacena, Nathan Seiberg, Edward Witten, Eva Silverstein, Shamit Kachru? Do you think the texts about you, your discoveries, and your colleagues are inaccurate? You may edit them, too.

Of course that Wikipedia is not perfect. Being perfect in the real world is the same thing as being dead. For example, Shahriar Afshar tries to maintain a promotional article about his own "revolutionary" experiment (that we discussed here) and another, very powerful clique of Wikicrackpots will never allow the Wikipedia readers to learn why loop quantum gravity is wrong. (I was informed that a certain "Tweet Tweet" has identified himself or herself in the previous sentence, and I can confirm that the identification is correct.) If certain paradigms are popular within the community of the Wikieditors, it is reasonable to expect that the presentation will be twisted in a certain way. Nevertheless, if one looks at the final result, it looks unexpectedly balanced to me.

Some of the recent incidents have been covered in ridiculous ways by the mainstream media. For example, Brian Chase has made a good prank and edited the page about John Seigenthaler Sr. to argue that he was participating in the assasination of John F. Kennedy. Because the page about John Seigenthaler Sr. is obviously not the most attractive page at Wikipedia, it took nearly half a year before the apparent hoax was found and pointed out to Seigenthaler himself. Media, including FoxNews, then celebrated Seigenthaler as a hero and the amount of positive feedback he received exceeded any possible damage caused by the Wikipedia article by several orders of magnitude. He should definitely be very grateful not only to Brian Chase but to all people behind Wikipedia.

Even though I think that such pranks are funny, I also support some recent policies meant to regulate the editing process of Wikipedia. For example, the page about George W. Bush - and several pages that ignite a similar amount of controversy - can only be edited by registered users whose accounts are not new. In my opinion, this should become the default rule for all pages that have been shown to be controversial.

Hubble: cosmic string verdict by February

Let me remind you that the Hubble pictures of the cosmic-string-lensing CSL-1 candidate, taken by Craig Hogan et al., should be available by February 2006. Ohio's Free Times interviews Tanmay Vachaspati who has studied cosmic strings for 20 years. (Via Rich Murray.)

Evolution and the genome

The editors of the Science magazine have chosen the evolution - more precisely, the direct observations of evolution through the genome - to be the scientific breakthrough of 2005.

• Darwin wins in 2005

I think it is a fair choice. The analyses of the genome are likely to become a massive part of "normal science" with a lot of people working on it and a lot of successes and potential applications for the years to come. I expect many discoveries in this direction to shed light on the past lifeforms; on the explicit relationships between the currently existing species and their common ancestry; the evolutionary strategies of diseases and our strategies to fight them; and finally on the new possible improvements of the organisms that are important for our lives, and - perhaps - the human race itself.

Stem cell fraud

Incidentally, the breakthrough of the year 2005 for the U.S. particle physics is called "Particle physicists in the U.S. would like to forget about 2005" which may be fair, too. However, the situation is still better than in stem cell research where some of the seemingly most impressive results in the past years - those by Hwang Woo Suk from Korea - have been identified as an undisputable fraud. Steve McIntyre points out that Hwang was one of Scientific American's 50 visionaries together with Michael Mann who, after a comparable incident (one involving the "hockey stick graph"), was not fired but instead promoted. Steve McIntyre has also written the world's most complete chronology of the scandal. Google tells you more about the sad story of scientific consensus behind the former Korean national hero. It's amazing how this fraud that no one could apparently reproduce immediately gained 117 citations. Should we believe the Koreans - without testing them - because they are so skillful in manipulating the chopsticks? Or perhaps because it is nice to see that the U.S. science is falling behind - "certainly" because of George W. Bush? Have the people in that field lost their mind? Or is it really the case that the whole cloning field - or perhaps even all Bush critics in the world - are participating in a deliberate international fraud?

Back to the positive story: the genetic evidence for evolution.

New tools make questions solvable

New scientific methods and technologies often have the capacity to transform an academic dispute whose character used to be almost religious into an obvious set of facts. Let me give you two examples.

The death of hidden variables

The first example are Bell's inequalities. Before they were found, it was thought that no one could ever determine whether the quantum mechanical "randomness" was just an emergent process based on some classical "hidden variables"; this debate was thought to be a philosophical one forever. After the inequalities were found and the experimental tests confirmed quantum mechanics, it became clear that the quantum mechanical "randomness" is inherent. It cannot be emergent - unless we would be ready to accept that the underlying hidden variables obey non-local (and probably non-relativistic) classical laws of physics which seems extremely unlikely.

Sun's chemistry and spectroscopy

My second example goes back to the 19th century. Recall that the philosopher Auguste Comte, the founder of positivism, remarked in his "Course de philosophie positive" that the chemical composition of the Sun would forever remain a mystery.

It only took seven years or so, until 1857, to show that Comte was completely wrong. Spectroscopy was discovered and it allowed us to learn the concentration of various elements in the Sun quite accurately. Unfortunately, this discovery came two years after Comte's death and therefore he could not see it. Incidentally, two more years later, in 1859, Darwin published his theory.

The last we-will-never-know people

Many people have been saying similar things about physics in general: physics could never determine or explain UV or XY - and all of these people have already been proved wrong except for those who argue that the parameters of the Standard Model can't be calculated with a better accuracy than what we can measure; the latter group will hopefully be proved wrong in our lifetime.

Speed of evolution

What do the new discoveries tell us about the evolution? First of all, evolution is not fuzzy. It is "quantized", if you allow me to use physics jargon, and the evolutionary changes are directly encoded in the genes that can be equally easily decoded.

A related and equally important observation is that the evolutionary changes are quite abrupt. We have never observed skeletons of bats with one wing and similar creatures - as the creationists (including those in a cheap tuxedo, using the words of pandas from level 2) have been quite correctly pointing out for decades. Indeed, it often takes a single mutation only to establish a new species.

Many mutations are harmful and they become immediately a subject of natural selection. Some mutations allow the organisms to survive. All these changes were making the tree of life ramify all diversify - and they are still doing so although this process is nowadays slower than some other types of developments.

Reply to Pat Buchanan

Let me finally choose an article from Dembski's blog in which he reposts

• Buchanan on Marx and Darwin

It is entertaining to see a text whose political part is more or less true but the scientific one is so clearly and completely wrong. Let's clarify some errors of Buchanan's:

• In his “Politically Correct Guide to Science,” Tom Bethell ...

Surprisingly, the book is called "Politically Incorrect...", not "Politically correct...". Tom Bethell is rather unlikely to be politically correct.

• For generations, scientists have searched for the “missing link” between ape and man. But not only is that link still missing, no links between species have been found.

Because there are no highly refined intermediate links of the type Buchanan suggests; one mutation often makes these changes occur and the evolution is far from being a smooth, gradual, and continuous process. However, chimps' genome has been decoded. We can not only see that chimpanzees are our closest relatives but also deduce the existence of a common ancestor. Our relationship with the chimps is no longer a matter of superficial similarity; a long sequence of bits - a microscopic genetic information - reveals a much more detailed picture.

• As Bethell writes, bats are the only mammals to have mastered powered flight. But even the earliest bats found in the fossil record have complex wings and built-in sonar. Where are the “half-bats” with no sonar or unworkable wings?

Half-bats with unworkable wings are predicted by Darwin to die quite rapidly, so there should not be too many fossils around. Observations seem to confirm this prediction of Darwin's theory, too. Indeed, such changes must proceed quickly and today we know that a single change of the genome is capable to induce these macroscopic changes.

• Their absence does not prove — but does suggest — that they do not exist. Is it not time, after 150 years, that the Darwinists started to deliver and ceased to be taken on faith?

Don't tell me that you don't think that this comment of Pat Buchanan sounds just like Peter Woit. ;-) Let me remark, in both cases, that 150 years and maybe even 30 years is probably a long enough time to start to think about the possibility that the "alternatives" to evolution or string theory can't ever work.

• No one denies “micro-evolution” — i.e., species adapting to their environment. It is macro-evolution that is in trouble.

First of all, it is not a trouble - it was chosen to be the most spectacularly confirmed scientific paradigm by discoveries done in 2005. Second of all, the difference between "micro-evolution" and "macro-evolution" is just a quantitative one. Most of the errors that Buchanan and other creationists do can be blamed on this particular error in their thinking: they incorrectly believe that objects in the world can be dogmatically and sharply divided to alive and not alive; intelligent and not intelligent; micro-evolution and macro-evolution. (And of course, someone would also like to divide the whole human population to believers and non-believers.)

Neither of these categories can be quite sharply defined. Even though the species are defined by "discrete", "quantized" bits of information encoded in the genome, it does not mean that each species can be classified according to some old, human-invented adjectives. Science does not break down but the adjectives used in the unscientific debate - or the Bible - certainly do break down when we want to understand life (or the whole Universe, for that matter) at a deeper level.

The world is full of objects whose "aliveness" is disputable - such as the viruses. The same world also offers evolutionary steps that can be safely classified neither as micro-evolution nor as macro-evolution. Finally, there are many organisms in the world that are only marginally intelligent, and I am afraid that this group would include not only chimps but maybe also some syndicated columnists. ;-)

• The Darwinian thesis of “survival of the fittest” turns out to be nothing but a tautology. How do we know existing species were the fittest? Because they survived. Why did they survive? Because they were the fittest.

I completely agree that the operational definition of the "fittest" is circular. It is the whole point of Darwin's notion of natural selection that "being the fittest" and "have a higher chance to survive" are equivalent. However, there is also a theoretical way to derive whether an animal is "the fittest" which can be used to predict its chances to survive. Such a derivation must, however, use the laws of nature in a very general sense - because it is the laws of nature that determine the chances to survive. Sometimes it is easy to go through the reasoning. A bird without legs in between the tigers does not have a bright future. Sometimes the conclusion is much harder to make. But the main message is that these questions can be studied scientifically and the answers have definitely influenced the composition of the species on our planet.

• While clever, this tells us zip about why we have tigers.

"Why we have tigers?" is not a scientifically meaningful question unless a usable definition of a tiger is added to it as an appendix. The Bible can answer such verbal, non-scientific question, by including the word "tiger" in one of the verses (and by prohibiting everyone to ask where the word and the properties of the animal came from). Science can only answer meaningful questions. For example, we may try to answer the question why the hairy mammals - beasts of prey - whose maximum speed exceeds 50 mph have evolved.

• It is less a scientific theory than a notion masquerading as a fact.

It is somewhat entertaining that the word "notion" is apparently supposed to have a negative meaning. Notions, concepts, and ideas are an essential part of our theories - and the word "theory" is not negative either because the best and most reliable things we know about the real world are theories based on notions and ideas.

• For those seeking the source of Darwin’s “discovery,” there is an interesting coincidence.

Those who judge the validity of a scientific theory according to the coincidences that accompanied its original discovery are intellectual equivalents of chimpanzees, and therefore they are another piece of evidence for evolutionary biology.

• As Bertrand Russell observed, Darwin’s theory is “essentially an extension to the animal and vegetable world of laissez-faire economics.”

I completely agree with that. This is why both Darwin's theory as well as capitalism are the leading paradigms among their competitors. Many general ideas are shared by these two frameworks; other ideas are quite independent.

• If it is science, why can’t scientists replicate it in microcosm in a laboratory?

Of course that they can replicate many particular examples in their labs. They can't replicate them exactly with the same speed as they occured in Nature because such labs would have to cover 510 million squared kilometers and they would have to work for 5 billion years. Nevertheless, the process can be sped up in many ways, at least in some particular situations.

• If scientists know life came from matter and matter from non-matter, why don’t they show us how this was done, instead of asserting it was done, and calling us names for not taking their claims on faith?

Let me assume that the first sentence talks about the reheating, to be specific. The reason why I probably can't show Pat Buchanan how different forms of matter or non-matter are transforming into each other according to the laws of quantum field theory or string theory - and why we know that it is the case without any religious beliefs - is that Pat Buchanan apparently does not have a sufficient intelligence to understand my explanations. It's that simple.

• Clearly, a continued belief in the absolute truth of Darwinist evolution is but an act of faith that fulfills a psychological need of folks who have rejected God.

That may well be the case but such an ad hominem observation is completely irrelevant if there are clear proofs that the picture is correct.

• Hence, if religion cannot prove its claim and Darwinists can’t prove their claims, we must fall back upon reason, which some of us believe is God’s gift to mankind.

Unfortunately for Mr. Buchanan, this is not our situation because the Darwinists can prove their claims quite convincingly. By the way, the discovery of evolutionary biology is certainly one of God's big gifts to mankind, too. ;-)

• And when you consider the clocklike precision of the planets in their orbits about the sun and ...

The motion of the planets is exactly predictable by our theories. It is clocklike but not atomic-clock-like. Indeed, we can easily measure the irregularities in their motion - which means, among other things, that we will have to insert a leap second between 2005 and 2006 once again to counterbalance Nature's (or God's?) imperfection, so to say.

• ...the extraordinary complexity of the human eye, does that seem to you like the result of random selection or the product of intelligent design?

It is the result of very sophisticated laws of Nature - physics, biology, and so on - whose important "emergent" feature responsible for much of the progress is the natural selection. Natural selection is not quite random even though it can sometimes look so at short enough time scales.

• Prediction: Like the Marxists, the Darwinists are going to wind up as a cult in which few believe this side of Berkeley and Harvard Square.

It would be a bit nicer if only a few around Harvard Square believed marxism. ;-)

Merry Christmas

Background sound (press ESC to stop): Jakub Jan Ryba's "Czech Christmas Mass" (Hey master, get up quickly); a 41:39 MP3 recording here



Merry Christmas! This special season is also a great opportunity for Matias Zaldarriaga and Nima Arkani-Hamed to sing for all the victims of the anthropic principle who try to live in the bad universes (audio - sorry, the true artists have not been recorded yet):

• WE WISH YOU A TINY CC
  WE WISH YOU A TINY CC
  WE WISH YOU A TINY CC
  SO YOU GET GALAXIES!
  
  GOOD TIDINGS WE BRING,
  FROM FROM VILENKIN
  DON'T CRY IF YOUR WORLD SUCKS
  IT'S MUCH BETTER OUT THERE
  
  WE WISH YOU A TINY HIGGS VEV
  WE WISH YOU THE RIGHT UP QUARK MASS
  WE WISH YOU A GOOD WEAK SCALE
  AND A HAPPY VACUUM.
  
  You can't live until you get stars
  You can't live until you get stars
  You can't live until you get stars
  So bring them right here.
  
  GOOD TIDINGS WE BRING,
  FROM FROM VILENKIN
  DON'T CRY IF YOUR WORLD SUCKS
  IT'S MUCH BETTER OUT THERE
  
  WE WISH YOU A TINY CC
  WE WISH YOU A TINY CC
  WE WISH YOU A TINY CC
  IN A BIG MULTIVERSE!

Yes, your humble correspondent sees it differently (audio).



Single vevs

• Trashing discretuum,
  with a one-choice vacuum.
  Laughing with our boss
  and with David Gross... (( Ha, ha, ha ))
  
  Vevs are 'bout to ring
  Making spirits bright
  What fun it's to determine
  the one background that's right.
  
  Oh, single set [of] single vevs, single all the way!
  Grab all other vacua and throw them right away.
  Single set [of] single vevs, single all the way!
  Oh, what fun it is to thrash anthropic beasts of prey.
  
  Landscape is now gone,
  so let's have some fun
  Take Witten along
  And sing predictive song.
  Begin with the state
  Two-fourty-eight E-eight
  Start to calculate the numbers
  and crack! You won't be late.
  
  Oh, single set [of] single vevs, single all the way!
  Grab all other vacua and throw them right away.
  Single set [of] single vevs, single all the way!
  Oh, what fun it is to thrash an..thropic beasts of prey.

Incidentally, the most famous classical old Czech Christmas carol "Nesem vám noviny" (lyrics, imprecise English lyrics, LM audio) is also sung by those who bring you good news from the landscape of Bethlehem.

E=mc2: a test ... interplay between theory and experiment

An experiment that is claimed to be the most accurate test of Einstein's famous identity "E=mc²" has been performed by physicists on the other side from the Central Square - at MIT.

• Globe and mail reports

Their accuracy is 55 times better than the accuracy of previous experiments. They measured the change of the mass of nucleus associated with the emission of energy after it absorbs a neutron. I find their promotion of the experiment slightly dishonest:

• "In spite of widespread acceptance of this equation as gospel, we should remember that it is a theory," said David Pritchard, a professor of physics at MIT, who along with the team reported his findings in the Dec. 22 issue of Nature. "It can be trusted only to the extent that it is tested with experiments."

The words "it is [just] a theory" remind me of something. The formula is not just "some" theory. It is an inevitable, robust, and rather trivial consequence of special relativity - a theory that has been tested in hundreds of other ways. Many different experimental constraints are known and many of them are more stringent than those from the current experiment. Naively and dogmatically speaking, the formula can only be trusted to the extent that it is tested with similar experiments.

Realistically speaking, the formula - and many other formulae - can be trusted well beyond these experiments. Everything depends on the amount of reasoning that we are allowed to perform with our brains in between the experiments. It is not true in science that every new experiment is really new. The whole goal of science is that we know the result of a huge class of experiments without actualling performing them. We can make predictions. Very general predictions and less general predictions. And science is able to do such things, indeed. If we are allowed to think a lot, the experiment is not terribly thrilling and its result is known in advance. There is just no way how we could design a theory in which the results will be different that would be simultaneously compatible with the experiments that have already been made.

Also, a theorist would not say that such an experiment is testing "E=mc²"; it is very hard to explain to a particle physicist why one thing they measure is "mass" while the other is something else, namely "energy". They just measure several different forms of the same quantity - one that can be called either mass or energy. Finally, if some discrepancy were found, no sane physicist would interpret it as a violation of this particular formula. It's because we have no candidate framework that would be consistent with basic properties of the Universe but that would violate "E=mc²". For example, Noether's theorem only guarantees the conservation of one quantity associated with the time-translational invariance - it is the total mass/energy. Of course that in the case of an experiment that would disagree with the theory, we would have to look for other, more technical and subtle explanations of such a discrepancy.

But all these comments are completely hypothetical because this is just a very low-energy experiment described by well-known physics and we know that that there won't be any discrepancies.

Isolating data to compare

There is one more topic related to the interactions between theories and experiments. Steve McIntyre is trying to clarify some confusions of Rasmus Benestad here. Benestad writes, among many other bizarre things, the following:

• When ARIMA-type models are calibrated on empirical data to provide a null-distribution which is used to test the same data, then the design of the test is likely to be seriously flawed. To re-iterate, since the question is whether the observed trend is significant or not, we cannot derive a null-distribution using statistical models trained on the same data that contain the trend we want to assess. Hence, the use of GCMs, which both incorporates the physics, as well as not being prone to circular logic is the appropriate choice.

In other words, his proposed strategy is to pick a favorite model of yours - a model that predicts a "signal" - and to work on showing that the observations are consistent with the model. Benestad clearly believes that it is not necessary to try to verify the hypothesis that the observations are a "signal" in the first place. The statement that we observe a "signal" not noise is a dogma for him. No analysis of the "natural background" and its statistical parameters is required; in fact, it is not even allowed, Benestad argues.

I find his reasoning circular, flawed, and downright stupid. This is exactly how crackpots operate: they almost always want to make a big discovery - to find a huge signal - without learning what is actually the "background" above which their hypothetical signal should exist. To be sure: of course that we must first know what to expect without a conjectured new effect if we want to decide whether the new effect exists. And if such expectations are determined experimentally, of course that we are not allowed to include the new effect when we determine the expectations. (This reminds me of the fermionic zero mode debate.)

Let me try to describe the situation in one more way. Rasmus is not right when he says that we cannot derive a null hypothesis from the datasets themselves. This is what we’re doing in many situations in science - every time when an actual nontrivial check of our theories is provided by reality. Let us look at an example. We have thousands of such examples in physics.

CMB and the isolation of theory and experiment

When the cosmic microwave background was discovered, no one had a complete theory. It was determined from the data that the microwave background was thermal and what was its temperature. Namely 2.7 kelvins. Of course one had to know that “being thermal” was a natural answer about the structure of radiation; in fact, the CMB is still the most accurate natural thermal blackbody curve we have seen so far. But you don't need to understand or calculate some situations in general relativity to understand that the observed radiation is approximately thermal!

The fluctuations of the temperature were determined from the data, too. Their dependence on the scale was also found and the spectrum was seen to be approximately scale-invariant. Finally, deviations from the scale invariance are also observed from the data.

The main conclusions - thermal curve; scale-invariant fluctuations; violations of scale invariance in a particular direction; various correlations etc. - are derived directly from the observed data.

Then you independently pick your Big Bang theory and you see that it naturally explains the thermal distribution because everything was in equilibrium 300,000 years after the Big Bang when the radiation was created. Also, inflation that took place a long time before this era - a fraction of second after the Big Bang - explains scale invariance. And some more detailed calculations that depend on the inflationary model also predict some deviations from the scale invariance, and many models may be falsified in this way. In fact, the last observation - the deviations from scale invariance - do not yet have a generally acceptable theoretical description even though people can, of course, fudge their models to get an agreement, much like the climate modellers are doing so.

What I want to say is that there must separately exist conclusions derived from the experiments; and conclusions derived just from the theory. And these two sets of conclusions must be compared. If someone is showing an agreement simultaneously by twisting and cherry-picking the data according to the theory and fudging the theory according to the data, merely to show that there is a roughly consistent picture, then it is no confirmation of “the” theory. In fact, there is no particular theory, just a union of ill-defined emotions whose details can be changed at any time. It’s not science and one cannot expect a "theory" obtained in this way to have any predictive power. This is how the priests in 15th century argued that the real world is consistent with the Bible.

The order of discoveries must be arbitrary

A correct scientific theory must be able to make predictions of some feature(s) of the observed data before the data is observed - this is why it is called a prediction - and the same thing holds vice versa. Nontrivial experimental facts must be determinable and describable without the ultimate theory before this theory is found, otherwise they cannot be used to determine the theory. In other words, it must always be a historical coincidence whether the theory or the experiment was the first group that gave the result.

Of course I am not saying that the actual evolution of science is decoupled to theorists and experimentalists who don’t talk to each other. What I am saying is that they should not be talking to each other - and they should never build their research on their friendship - when they try to determine whether a theory agrees with some particular observations.

In this particular case, whether or not some heating is an example of natural persistence or an effect caused by XY is, of course, an important scientific question. It is much more likely and “default” that it is caused by some long-term persistence because if it were not, there are still very many factors XY that could be really causing it. If we don’t have an observation that would suggest that the persistence does not exist (for example accurate enough observations of the 15th century temperature), we should not assume that it does not exist. Of course that it probably does, and a goal of the scaling papers is to find phenomenological laws that would help to determine the color of the noise - and henceforth also the persistence at various time scales - from the data, regardless of some additional effects caused by anyone else.

The qualitative question whether the persistence exists is quite clear. It does. The noise exists at all scales. The real question is a quantitative one.

Background vs. signal

It is extremely important to know what is the “natural background” if we try to figure out whether there is a new “effect”. Some people like Rasmus Benestad just don’t want to study the natural background at all - they immediately want to get effects (and attention of the press in which they're pretty successful because many journalists are pretty dumb) - which is why I think that they are crackpots. As mentioned previously, one of the defining features of crackpots is that they want to make big discoveries before they learn what is the science describing the “simpler” phenomena before their discovery.

Let me say why their research is defective in one more way.

Whenever we try to design scientific theories that describe something, we must know which quantities in reality will be described by our theories and we must be able to isolate them.

By isolating them, I mean both theoretical as well as experimental isolation. In theories we must know - or at least feel - that the effects we have neglected do not change our predictions too much. In experiments we must know - or at least have rational reasons to believe - that the effects we observe are not caused by something else, something “more ordinary”. When we try to observe telepathy, for example, we must know that the people are not communicating by some more "natural" methods.

The climate modellers almost never try to follow these lines. They have a completely vague, sleeky set of ideas that predict anything and everything - warming, cooling, bigger variations, smaller variations, more hurricanes, less winds, increased circulation, diminished circulation, more ice in Antarctica, less ice in Antarctica, and so forth - and then they’re arguing that the data agrees with these predictions. Of course they emphasize the points whenever they agree and de-emphasize them whenever they disagree. This is not science.

Of course there is no direct way how one can ever construct a scientific framework out of this mess. To do science, one must focus on a limited class of questions that are sufficiently well-defined and that have a chance to be “cracked” by a theory. I am sure that there are many nice laws about the climate that we don't know yet, and I am equally sure that the work of most of the "mainstream" climate scientists today is not helpful in revealing these laws.

When we try to argue that the humans are suddenly dictating the climate trends - after 5 billion years when they were dictated by other, more natural things - it is a rather extraordinary conjecture that deserves extraordinary evidence. For getting any evidence, it is absolutely necessary to understand how the climate was behaving for 5 billion years before the hypothetical “revolution” occured around 1917. We must know what were the fluctuations and how they depended on the time scale. We can only learn such things reliably by observing the real world. Only once we know the background, we can study the additional effects.

Studying additional trends above a background that we don’t need to understand is equivalent to the Biblical literalism.

Summary

Some readers may feel that the two parts of this text contradict each other because I defend theory in the first part and the observations in the second part. However, I am convinced that every sane scientist (and informed layman) knows that both theory as well as experiments are important. My goal was certainly different from changing the balance to one side. My goal was to emphasize that science should be looking for robust conclusions and theories and it should be attempting to find the situations in which the phenomena exhibit themselves in the sharpest possible way. And a necessary principle to achieve this goal is to try to follow these principles:

• try to isolate the "signal" that you are interested in as well as you can
• when your signal exists above a certain "background", you must definitely try to understand the background first
• if you can find an idealized situation in which one signal is isolated from some other effects that you're not interested in, study this situation
• if you cannot find an idealized situation and if everything looks like quantitatively undescribable chaos to you that you want to match by a computer-generated chaos, then it means that you still misunderstand what's going on; avoid the quagmire and return to the point #1
• if you have a theory, be sure to deduce and decide what kind of quantities the theory should be able to predict
• if your theory only agrees with some observations, never fool yourself and never try to de-emphasize the observations you know to disagree with your theory
• if your theory or model only agrees "roughly" with 24 features of the data but there are 25 parameters or assumptions that led to your model, be sure that you can't claim that you established your model or its assumptions
• isolate the assumptions of your theories (and open questions) from each other and try to test them separately whenever you can
• if you try to explain experimental data, always ask whether there exists a simpler and more natural theory than yours that would be able to do approximately the same job
• if there is a more natural theory with less parameters, go for it
• never believe that your theory is superior just because it is using the buzzwords - or approximate concepts and laws - that are more frequent in physics; this is not how the better theories are identified

TeX for PowerPoint: TeX4PPT

Aurora is a new commercial LaTeX system for MS Office

Some readers may have installed TeXpoint as an add-in to their PowerPoint. Let me now mention that

• TeX4PPT

is probably superior and everyone who uses TeX as well as PowerPoint should install this piece of free software. In this framework, you may create a new "text box" using the drawing toolbar. Inside the text box, you may write some $tex$. When you're finished, you right-click and choose TeXify. It will convert the text box into a nice piece of LaTeX. One internal advantage over TeXpoint is that it is directly the DVI that is being converted to Microsoft's own fonts. (TeXpoint was also generating a postscript as well as an image.) This means, among other things, that the text respects the background.

The results look very good. The TeX results may be resized, the color may be changed, and so forth. Much like with TeXpoint, TeX4PPT adds its own menu among your PowerPoint menus. The menu allows you to configure your TeX4PPT, add LaTeX macros, change settings, fine-tune fonts, and see help pages.

The father of Bott periodicity died

Via David G.

Raoul Bott - a Harvard mathematician who was fighting against cancer in San Diego and who discovered, among other things, the Bott periodicity theorem in the late 1950s - died the night of December 19-20, 2005.

• Announcement at Harvard

His mother and aunts spoke Hungarian. However, his Czech stepfather did not, and therefore the principal language at home was German. At the high school, on the other hand, he had to speak Slovak. His nanny was English which helped young Bott to learn authentic English. To summarize this paragraph: one should not be surprised that Bott hated foreign languages.

Mathematics was much more important language for him, and some people remember him very well. See articles by Jacques Distler, Peter Woit, and Sean Carroll.

Blog of WWW inventor

The person who invented the World Wide Web has started to write

• his personal blog.

No, it is not a blog of Al Gore - Al Gore has only invented the Al Gore rhythms. The new blog belongs to Tim Berners-Lee who made his invention while at CERN, and currently lives here in Boston.



Figure 1: The first web server in the world (1990)

MIT talk: a theory of nothing

Today, John McGreevy gave an entertaining MIT seminar mainly about the theory of nothing, a concept we will try to define later. The talk described both the work about the topology change induced by closed string tachyon condensation as well as the more recently investigated role that the tachyons may play for a better understanding of the Big Bang singularity. Because we have discussed both of these related projects on this blog, let's try to look at everything from a slightly complementary perspective.

Defining nothing

First of all, what is nothing? John's Nothing is a new regime of quantum gravity where the metric tensor - or its vev - equals zero. This turns out to be a well-defined configuration in three-dimensional gravity described as Chern-Simons theory. It is also the ultimate "paradise" studied in canonical gravity and loop quantum gravity.

Does "nothing" exist and is there anything to study about it? I remain somewhat sceptical. If the metric is equal to zero in a box, it just means that the proper lengths inside the box are zero, too. In other words, they are subPlanckian. The research of "nothing" therefore seems to me as nothing else from the research of the subPlanckian distances. This form of "nothing" is included in every piece of space you can think of, as long as you study it at extremely short distances. And we should not forget that the subPlanckian distances, in some operational sense, do not exist. I guess that John would disagree and he would argue that nothing is an "independent element" of existence; a phase in a phase diagram. I have some problems with this picture.

Tachyons create nothing

The next step in the system of ideas that John nicely promoted is the paradigm that the tachyons are very important for a correct understanding of "nothing". We know that the open string tachyons get a vev that describes a complete destruction of the original D-brane (or a D-brane pair) - the best state of "open string nothing" you can imagine. The twisted closed string tachyons of Adams, Polchinski, Silverstein describe the destruction of the orbifold singularity.

Allan, John, Eva, and their collaborators have extended this reasoning into localized winding closed string tachyons whose condensation is able to change the spacetime topology. For example, if you compactify two dimensions (out of ten) on a genus "g" Riemann surface, the condensation of the winding tachyons is able to cut a handle and reduce the genus. This perturbative instability is continuously connected with Witten's bubble nucleation.

This event also changes the Witten index - if it exists in this nonsupersymmetric background at all - and John argued that there are some "dust states" left behind in the region of nothing where the handle disappeared. I was not the only one who did not understand whether they feel lonely there - and more generally, what is exactly the physical relation between them and the rest of the space where the observations can actually be done. Do they have any observable consequences?

I also remain a bit cautious about the identification of the nothing we defined at the beginning (g_{mn}=0) and this new nothing (T=T_{0}) described as a tachyon condensate. These are - at least a priori - two different conditions. Also, as a person who has spent one half of his life behind the iron curtain, I find it difficult to believe that there is "nothing" behind the iron curtain. Nevertheless, one of the statements is that there is "nothing" behind the Liouville wall which sounds somewhat analogous to the iron curtain. A counterpart of the Liouville wall that is localized in time is used by John and Eva to screen the undesirable features of the Big Bang singularity.

I also remain unconvinced that there exists any CFT of the type they conjecture that is conformal even at the point "t=0", a CFT in which the dilaton gradient may be neglected (although the gradient seems necessary to generate the central charge from the missing spacetime coordinates inside "nothing"), and where the condensation of the tachyon remains localized to the vicinity of the Big Bang.

This discussion may become too philosophical very quickly but I strongly feel that the basic questions here have an almost philosophical character and many of them must be answered before one tries to study details. And many questions were asked during the talk; some of them may have been treated by John as jokes, but I personally found them as serious as the rest of the discussed topics. Hopefully John will tollerate my opinion that some questions must simply be treated as serious questions once these possible mechanisms are studied seriously.

Splitting the Universe

For example, the winding tachyon condensation can in principle be able not only to reduce the genus but also to split the Universe (i.e. split the compact manifold that exists at each point of the large dimensions) into two independent pieces. I like this possibility because it could lead to a vacuum selection mechanism that makes most vacua unstable except for e.g. the heterotic Standard Model vacua with the minimal values of the Hodge numbers; every other Universe could find a way to split into "simpler" vacua with smaller Hodge numbers. This is based on my belief that simple vacua in string theory - and in science in general - are preferred not only by our approach based on Occam's razor (those who prefer the Rube Goldberg machines will surely forgive me that I hijacked the word "our") but they are also preferred by Nature. We've seen this principle in action many times.

Attracting other Universes and wormholes

This is a nice possibility but there is another one which is even more drastic. Revert the process we just described. Prepare the radiation exactly in such a way that it will "reconnect" our Universe with another Universe that is still "waiting to join us" in some virtual reality - reality that was geometrically disconnected from our world at the beginning. Can such a thing happen? I think that any sane person would say that in practice, it will be impossible at least in this century. ;-) It is as impossible in practice as the creation of an "S-brane"; John agrees.

On the other hand, John mentioned this science-fiction topic, which is why it would be a good idea to have at least some approximate answers to some obvious questions like What is the probability that our experiments will be able to reconnect us with a different Universe? (Yes, of course, this question has been asked, too.) If someone proposes that such a process is in principle possible, then the questions like this one are legitimate ones and they should not be treated as jokes. Needless to say, there exists a certain set of possible answers that may show that the picture is inconsistent with the very basic properties of our Universe. I personally find it very likely that pure thought is enough to identify these possible mechanisms as inconsistent. These existential questions affecting similar scenarios should be studied simultaneously with some more detailed questions, if not before them - because we don't want to study something that is inconsistent.

Open questions

At any rate, there are many very provocative and intriguing questions raised by this work that is very stimulating but also unlikely to be accepted as the "final answer", for example

• Does it make sense to study the very early, "t=0" behavior of our Universe at all? My answer is Yes.
• Does it make sense to study physics of the beginning while keeping the initial conditions completely arbitrary? My answer is No.
• Can the topology of space be changed? The answer is Yes.
• Can the number of components of the Universe - the "spatial manifold" - change? The answer is We don't know for sure.
• Can time start and end, and should we allow for a violation of unitarity in the finite neighborhood of the singularities?
• If the answer to the question about splitting the Universe to pieces is Yes, we should ask How quickly the two components of the Universe get decoupled? We don't know.
• Can this splitting of Universes play a role in destabilization of the majority of the landscape? We don't know; so far there is no clear indication that the answer is Yes.
• Can the process of splitting be reverted so that we force another Universe to join us? Probably not in practice - but in principle, we don't know.
• If we are able to change the topology of space, are we also able to create macroscopic wormholes and/or time machines? My answer is Probably no in practice, but we still don't know the answer in principle.
• Are such possibilities consistent with unitarity, or do they force us to modify something essential about the structure of physics?
• Can we reformulate everything in physics of perturbative string theory as a refined analysis of tachyon dynamics?
• Is the tachyon really so naturally useful for all these new proposed applications, or do we propose such links because tachyons have been fashionable for 7 years, after the decades in which they were discriminated against as "ugly inconsistencies"? ;-)

MIT talk: Susanne Reffert

Yesterday we went to MIT to see the talk by Susanne Reffert who will be finishing her PhD under Dieter Lüst and who will probably continue her investigation of string theory in Amsterdam, turning down offers from the KITP and CERN. And it was a very nice talk. First of all, she uses Keynote, an Apple-based alternative for the PowerPoint which reconciles TeX and animations into a consistent whole.

Moduli stabilization of F-theory flux vacua again

There have been too many points in the talk to describe all of them here. They studied, among other things, all possible orientifolded and simultaneously orbifolded toroidal (T^6) vacua of type IIB string theory, their resolution, description in terms of toric geometry, flops, and especially the stabilization of the moduli. One of the unexpected insights was that one can't stabilize the Kähler moduli and the dilaton after the uplift to the de Sitter space if there are no complex structure moduli to start with; rigid stabilized anti de Sitter vacua may be found but can't be promoted to the positive cosmological constant case. Some possibilities are eliminated, some possibilities survive, if you require all moduli to be stabilized.

Recall that the complex structure moduli and the dilaton superfield are normally stabilized by the Gukov-Vafa-Witten superpotential - the integral of the holomorphic 3-form wedged with a proper combination of the 3-form field strengths - while the Kähler moduli are stabilized by forces that are not necessarily supernatural but they are non-perturbative which is pretty similar. The latter nonperturbative processes used to stabilize the Kähler moduli include either D3-brane instantons or gaugino condensation in D7-branes.

At this level, one obtains supersymmetric AdS4 vacua. Semirealistic dS4 vacua may be obtained by adding anti-D3-branes, but Susanne et al. do not deal with these issues.

Nonperturbative superpotential: generated or not?

One of the interesting yet controversial points was their usage of the non-perturbative terms in the superpotential to modify the Dirac equations for the fermionic zero modes. Recall that D3-brane instantons wrapped on holomorphic 4-cycles - or, in a dual M-theoretical description, M5-brane instantons wrapped on some six-cycles - modify dynamics as nonperturbative effects.

But they only contribute to the superpotential W if you can find exactly two fermionic zero modes - let's say zero modes of the goldstino or the modulino - which means two solutions of the massless Dirac equation defined on the worldvolume of the D3-brane or M5-brane instanton. This is typically the case if you start with a vacuum that is supersymmetric at the tree level. Such a condition of supersymmetry requires that the 4-form d=11 field strength is of the type (2,2).

However, funny things happen. If you now accept that this instanton exists, you will generate a new term in the superpotential, W_{np}. When you solve the new equations of motion that include W_{np}, you will see that it is no longer true that the four-form is of the type (2,2). Other four-forms appear, too. The appearance of other components of the 4-form field strength than (2,2) modifies the Dirac equation for the fermionic zero modes; in fact you find out that all the zero modes are lifted. What does it mean? It means that the instanton does not generate a superpotential. That contradicts the assumptions that started this paragraph.

What does this contradiction mean? According to some people, it just means that the instanton calculation was done incorrectly. The non-perturbative corrections to the equations of motion arising from an instanton XY should not be included when you calculate the instanton XY itself. That would be like pushing a cart in front of the horse, and indeed, a colleague of mine claims that this is what our German friends are doing.

Superpotential survives

According to Susanne and her collaborators, the contradiction is resolved if one also modifies the supersymmetry variations by a term corresponding to W_{np}. A happy end is that their conclusion seems to be that there are two fermionic zero modes after all, and an agreement with the papers by Saulina and another paper by Kallosh et al. is achieved. But the exact assessment of the steps that lead to the conclusion remains a source of some slight controversy.

43rd known Mersenne prime: M30402457

One of the GIMPS computers that try to find the largest prime integers of the form

• 2^p - 1

i.e. the Mersenne primes has announced a new prime which will be the 43rd known Mersenne prime. The discovery submitted on 12/16 comes 10 months after the previous Mersenne prime. It seems that the lucky winner is a member of one of the large teams. Most likely, the number still has less than 10 million digits - assuming that 9,152,052 is less than 10 million - and the winner therefore won't win one half of the $100,000 award.

The Reference Frame is the only blog in the world that also informs you that the winner is Curtis Cooper and his new greatest exponent is p = 30,402,457. (Steven Boone became a co-discoverer; note added on Saturday.) You can try to search for this number on the whole internet and you won't find anything; nevertheless, on Saturday, it will be announced as the official new greatest prime integer after the verification process is finished around 1 am Eastern time. If you believe in your humble correspondent's miraculous intuition, you may want to make bets against your friends. ;-)

Actually I am so incredibly sure that you should bet thousands of dollars if someone is ready (and has the courage) to argue that I am mistaken and the exponent won't be 30,402,457. Trust me. Note that we predicted the previous Mersenne prime correctly, too. The new greatest prime looks like follows (more than 9 million digits are omitted):

• 315416475 … 652943871

The exponent may count the number of curves of a given genus in a particular elliptically fibered Calabi-Yau manifold. Or something else.

Temperatures' autocorrelation

Imagine that the Church would start to control the whole society once again. A new minister of science and propaganda would be introduced to his office. His name would not quite be Benedict but rather Benestad. How would they use scientific language to argue that the Bible in general and Genesis in particular literally describes the creation? They would argue that Genesis predicts water, grass, animals, the Sun, the Earth, and several other entities, and the prediction is physically sound. If anyone tried to focus on a possible discrepancy or a detail, Benestad would say that the heretics were pitching statistics against solid science.

The choice of the name "Benestad" will be explained later.

Do you think that the previous sentences are merely a fairy-tale? You may be wrong. First, we need to look at one scientific topic.

Cohn and Lins

Last month, we discussed the critical exponents that appear in the autocorrelation of the temperature measured at some place XY as a function of time.

Cohn and Lins have just published a paper in Geophysical Research Letters whose main point is completely obvious: the argue that because of long-term persistence (LTP), it is often difficult to distinguish "natural trends" based on "natural inertia" from "additional trends" that are caused by new factors. This fact makes it hard to calculate the statistical significance of the results.

Steve McIntyre discusses this topic in his characteristic, highly detailed and technical manner and he refers not only to a 2002 article by Pelletier but also to a text by Rasmus Benestad who does not like the paper of Cohn and Lins because it could be "misused by the septics". What does Rasmus Benestad have to say about the scaling laws of the autocorrelation?

• There is no information encoded in the statistics of the temperature averaged over different time scales, and people should not look at it.
• Cohn and Lins and whoever tries to study statistical properties of the autocorrelation is "pitching statistics against physics".
• Even if there were some information in the statistics, global climate models should not be tested whether they agree with the observed behavior.
• Global climate models are the holy principle of physics because they predict global warming, exactly what is seen in the real world, and therefore we must trust them.
• Global warming is also real, especially because it is predicted by the global climate models.
  
• Even if someone tried to test these models and if he found a disagreement (which seems to be the case), one should believe the models and not the observations because the models are governed by the "laws of physics" while the observed power laws are "just some statistics".
• "Statistics does not usually incorporate physically-based information, but derives an answer from a set of given assumptions and mathematical logic."
• Finally, Benestad claims that chaotic behavior cannot be found at scales longer than the length scale of a molecule.

The similarity with our Catholic thought experiment is breathtaking. The essence of science is very different from what Mr. Benestad is imagining:

• Observed data evaluated using statistical methods represent a completely essential part of the scientific research of any complex enough system and virtually all other systems.
• When we want to improve our understanding of a physical situation, it is absolutely necessary to try to compare our models with increasingly difficult sets of observed phenomena, datasets, and their statistical and other properties.
• The scaling laws are among the sharpest and scientifically most well-defined features of the physical systems that exhibit chaotic behavior.
• The weather and the climate exhibit chaotic behavior which is why the research of the scaling laws is relevant in this field.
• It is a complete nonsense that stochastic behavior only appears at the length scale of the molecules or shorter. It is enough to magnify the "water molecules" and the "seeds of dust" in order to see make the relevance of mathematics of the Brownian motion at longer distance scales relevant.
• The weather at many scales is analogous to such a magnified Brownian motion experiment.
• If a model is found to disagree with the observed long-term persistance and/or the observed autocorrelation laws at long time scales and if the statistical ensembles are large enough to allow us to make conclusions, then the model is falsified. It fails to be a credible model for predictions at these time scales.
• If 38 models are found to disagree with the observed features of the data, then all of them are falsified, and the number 38 does not make the degree of the falsification any weaker.
  
• If these models are as complicated as the Rube Goldberg machines, it does not make them "scientifically correct". Models can only become credible if they correctly describe and/or predict a large number of observables. This number must be greater than number of parameters that the model depends upon.
• While it is true that the classical behavior typically emerges at long distance scales and long time scales, it is not true that the effective long-scale theory is governed by the same physical laws that we would naively derive "microscopically" by ignoring the "quantum" and "chaotic" effects.
• For example, the critical exponents may be very different than the naive, classical exponents. Also, the parameters are renormalized, their signs may often change, and new effects are generated.
• Also, it is not true that the first ideas we have are the correct ones, even at macroscopic distances. Continental drift was also thought to be physically impossible, and testing our models against reality is completely necessary.
  

I claim that Rasmus Benestad misunderstands every single point listed above. His approach to the climate is exactly as unscientific as the approach of the fundamentalist Christians. He already knows the "truth" - based on very naive models of reality and on his misunderstandings of critical behavior described above - and he won't allow anyone to change a single letter about it by making comparisons with the "dirty statistics", i.e. with the observations of reality.

What's even more troublesome is that Rasmus Benestad is the kind of people that our society is hiring to study the climate. We're not yet in a scientific age because if our age were scientific, religious fanatics like this one would have to do completely different things than science.

Cosmological constant seesaw

One of the reasons why I have little understanding for the Rube Goldberg landscape machines is that their main goal is to explain just one number, namely the cosmological constant, which could eventually have a simple rational explanation. Let me show you two explanations leading to the same estimate. Recall that the observed cosmological constant is of order

$\rho\approx\frac{TeV^8}{m_{Pl}^4}$

This is almost exactly the same seesaw game with the scales like the neutrino seesaw game. In the case of the neutrinos, we assume the right-handed SU(5)-neutral neutrinos to acquire the GUT scale masses - which is almost the same thing as the Planck scale above - and the unnaturally small value of the observed neutrino masses comes from the smaller eigenvalue(s) of the matrix ((mGUT, mEW), (mEW,0)). Note that again, the neutrino masses are of the same order as the mass scale associated with the vacuum energy. This means that if the vacuum energy is, in some appropriate sense, a "2 x 2" matrix

$\left(\begin{array}{cc}0&+m_{SB}^4\\ +m_{SB}^4&-m_{Pl}^4\end{array}\right)$

then the eigenvalue closer to zero will be of the desired order. Let me propose one more mechanism to generate the seesaw for the cosmological constant. The vacuum energy of free fields may be computed as the integral of "sqrt(k^2+m^2)/2" (the zero-point energy of a harmonic oscillator) over the three-dimensional momentum space. This integral is quartically divergent. Normally we consider the following expression to be a result in the dimensional regularization

• m⁴

However, we are neglecting an infinite divergent term of order

• m_Pl⁴

Imagine that a better result for the integral is actually

$abs(m^4+im_{Pl}^4) = sqrt(m^8 + m_{Pl}^8)$

If it is so, you can Taylor-expand because "m_{Pl}" is so much larger. The term "m_{Pl}^4" cancels between bosons and their fermionic superpartners while the first uncancelled terms will be of order

$\frac{m_{boson}^8-m_{fermion}^8}{m_{Pl}^4}$

which is again of the right order of magnitude to match the observed vacuum energy because the numerator is of order "m_{SB}^8" where "m_{SB}" is the supersymmetry breaking scale. Yes, the calculation above does not really agree with the usual supergravity calculus but I think that we don't know whether the calculus is correct after SUSY breaking anyway.

Update: As we discuss here, our colleague from Brookhaven was brave enough to transform these ideas into a preprint based on the Wheeler-DeWitt equation.

Blogs against decoherence

If you're interested in a blog whose main enemy is decoherence - because they want to construct a quantum computer - see

• Superconducting blog

Everything new you need to know about the realization of quantum bits.

LHC on schedule

2005, the international year of physics, has so far been a flawless year for the LHC. 1000 out of 1232 magnets are already at CERN; 200 magnets have already been installed. See

• Press release

Update, September 2008: the protons start to orbit in the LHC on September 10th, 9:00 am, see the webcast. But the collisions will only start in October 2008, before a winter break. In 2009, everything will be operating fully. Click the "lhc" category in the list below to get dozens of articles about the Large Hadron Collider.

Distasteful Universe and Rube Goldberg machines

A famous colleague of ours from Stanford has become very popular among the Intelligent Design bloggers. Why is it so? Because he is the unexpected prophet that suddenly revived Intelligent Design - an alternative framework for biology that almost started to disappear. How could he have done so? Well, he offered everyone two options.

• Either you accept the paradigm shifting answer to Brian Greene's "Elegant Universe" - namely the answer that the Universe is not elegant but, instead, it is very ugly, unpredictable, unnatural, and resembling the Rube Goldberg machines (and you buy the book that says so)
• Or you accept Intelligent Design.

You may guess which of these two bad options would be picked by your humble correspondent and which of them would be chosen by most Americans. What does it mean? A rather clear victory for Intelligent Design.

The creationist and nuclear physicist David Heddle writes something that makes some sense to me:

• His book should be subtitled String Theory and the Possible Illusion of Intelligent Design. He has done nothing whatsoever to disprove fine-tuning. Nothing. He has only countered it with a religious speculation in scientific language, a God of the Landscape. Snatching victory from the jaws of defeat, he tells us that we should embrace the String Theory landscape, not in spite of its ugliness, but rather because of it. Physics should change its paradigm and sing praises to inelegance. Out with Occam’s razor, in with Rube Goldberg.

This statement is also celebrated by Jonathan Witt, another fan of ID. Tom Magnuson, one more creationist, assures everyone that if the people are given the choice to choose between two theories with the same predictive power - and one of them includes God - be sure that they will pick the religious one. And he may be right. Well, not everyone will make the same choice. Leon Brooks won't ever accept metaphysics and Evolutionblog simply applaudes our famous Stanford colleague for disliking supernatural agents. But millions of people with the same emotions as William Dembski will make a different choice and it is rather hard to find rational arguments that their decision is wrong because this is a religious matter that can't be resolved scientifically at this point. Discussions about the issue took place at Cosmic Variance and Not Even Wrong.

Intelligent design in physics

Several clarifications must be added. Just like the apparent complexity of living forms supports the concept of Intelligent Design in biology (when I saw the beautiful fish today in the New England Aquarium, I had some understanding for the creationists' feelings), the apparent fine-tuning supports a similar idea in physics. A person like me who expects the parameters of the low-energy effective field theory to emerge from a deeper theory - which is not a religious speculation but a straightforward extrapolation of the developments of the 20th century physics - indeed does believe in some sort of "intelligent design". But of course its "intelligence" has nothing to do with human intelligence or the intelligence of God; it is intelligence of the underlying laws extending quantum field theory.

Opposite or equivalent?

The anthropic people and the Intelligent Design people agree with each other that their pictures of the real world are exactly opposite to one another. In my opinion, this viewpoint about their "contradiction" already means a victory for Intelligent Design and irrational thinking in general. The scientific opinion about this question - whether the two approaches are different - is of course diametrically different. According to a scientific kind of thinking, there is no material difference between

• the theory that God has skillfully engineered our world, or has carefully chosen the place for His creation among very many possibilities
• and the theory that there are uncontrollably many possibilities and "ours" is where we live simply because most of the other possibilities don't admit life like ours

From a physics perspective, these things are simply equivalent. Both of them imply that the parameters "explained" by either of these two theories are really unexplainable. They are beyond our thinking abilities and it does not matter whether we use the word "God" to describe our ignorance about the actual justification of the parameters.

Both of these two approaches may possibly be improved when we reduce the set of possibilities to make some predictions after all. For example, we can find which vacuum is the correct one. Once we do so, the questions whether some "God" is responsible for having chosen the right vacuum, or whether no "God" is necessary, becomes an unphysical question (or metaphysical question, if you prefer an euphemism). Again, the only way how this question may become physical is that we actually understand some rational selection mechanism - such as the Hartle-Hawking wavefunction paradigm - that will lead to a given conclusion. Or if we observe either God or the other Universes; these two possibilities look comparably unlikely to me.

Without these observations and/or nontrivial quantitative predictions, God and the multiverse are just two different psychological frameworks. In this sense, the creationists are completely correct if they say that the multiverse is so far just another, "naturalistic" religion.

As they like to say, the two pillars of the religion of "naturalism" - Freud and Marx - are dead. And Darwin is not feeling too well, they add - the only thing I disagree with. ;-) Marx and Freud are completely dead, indeed.

Intelligent Design: answers to William Dembski

William Dembski is one of the most active intellectual promoters of Intelligent Design. He also has a blog

• Uncommon descent

in which he tries to collect and create various arguments and pseudoarguments to support his agenda. Just like a certain one-dimensional blog where every piece of news is projected onto the one-dimensional axis "may it hurt string theory?" - and if the projection is positive, the news is published - Uncommon descent evaluates articles and sentences according to their ability to hurt mainstream biology and to support Intelligent Design.



While I am among those who find all one-dimensional blogs and especially most of their readers kind of uninspiring, let me admit that in my opinion, neither of the two Gentlemen mentioned above seems to be a complete moron and many of their questions may deserve our time.

Dembski vs. Gross and Susskind

Because of the description of the blog above, it should not be surprising that Dembski celebrates and promotes both Susskind's anthropic comments indicating that many physicists have accepted opinions remotely analogous to Intelligent Design - as well as Gross's statement that we don't know what we're talking about.

Incidentally, when Dembski quotes David Gross, he says "remember that string theory is taught in physics courses". That's a misleading remark. String theory is only taught in courses on string theory, and with the exception of Barton Zwiebach's award-winning MIT undergraduate course, all such courses are graduate courses. What the advocates of Intelligent Design classes at schools want is definitely much more than the current exposure of the basic school and high school students to string theory.

Although Dembski and some of his readers may find these quotations of the famous physicists relevant, they are not. Maybe, we don't know what we're talking about when we study quantum Planckian cosmology, but we know what we're talking about whenever we discuss particle physics below 100 GeV, the history of our Universe after the first three minutes, and millions of other situations.

What Dembski wants to modify about our picture of the Universe are not some esoteric details about the workings of the Universe at the Planck scale or the mechanisms of vacuum selection. He wants to revert our knowledge about very low energy processes in physics and biology. That makes all his comparisons of biology with uncertainty in quantum gravity irrelevant.

Scientists may be confused about cutting-edge physics but that's very different from being confused about the insights in biology that have been more or less settled in the 19th century. Some scientists may think that a coincidence whose probability was 10^{-350} had to happen before our Universe was created or "chosen", but they don't need probabilities of order 10^{-10^{100}}

OK, the answers

Finally, let me answer 5 questions from Dembski's most recent blog article about microbiology:

• (1) Why does biology hand us technical devices that human design engineers drool over?
  

It is because the natural length scale of human beings is 1 meter. This is the size of humans as Nature created them. This is the length scale at which humans are very good in designing things. I claim that the human engineers are better than Mother Nature in creating virtually any object whose structure is governed by the length scale of one meter. The engineers are also better at longer distance scales - and the trip to the Moon is an example. Engineers had to develop some technology before the humans could directly affect matter at shorter distance scales than the size of our hands. We are getting better and we may get better than Mother Nature in a majority of nanotechnologies in the near future. William Dembski shows a remarkable short-sightedness if he justifies his opinion by saying that Nature is superior over technology - because it is all but guaranteed that technology will be taking a lead and the strength of Dembski's position will therefore definitely decrease with time.

At any rate, even the successes of engineers themselves reflect the miraculous powers of Mother Nature because engineers were created by Her, too. I am afraid that this fact is not appreciated by many advocates of Intelligent Design and many other people.

• (2) Why don’t we ever see natural selection or any other unintelligent evolutionary mechanisms produce such systems?
  

Of course that we do. When microprocessors are produced, for example, there is a heavy competition between different companies that produce the chips. Although Intel is planning to introduce their 65 nanometer technology in 2006, AMD may be ahead because of other reasons. This competition is nothing else than the natural selection acting at a different level, with different, "non-biological" mechanisms of reproduction, and such a competition causes the chips to evolve in an analogous way like in the case of animals. (If you want to see which factors drive the decisions about the "survival of the fittest" in the case of chipmakers, open the fast comments.)

Competition also works in the case of ideas, computer programs, ideologies, cultures, "memes", and other things. Indeed, we observe similar mechanisms in many contexts. The detailed technical implementation of the reproduction, mutation, and the rules that determine the survival of the fittest depend on the situation. Some of the paradigms are however universal.

• (3) Why don’t we have any plausible detailed step-by-step models for how such evolutionary mechanisms could produce such systems?
  

In some cases we do - and some of these models are really impressive - but if we don't, it reflects several facts. The first fact is that the scientists have not been given a Holy Scripture that would describe every detail how the Universe and species were created. They must determine it themselves, using the limited data that is available today, and the answers to such questions are neither unique nor canonical. The evolution of many things could have occured in many different ways. There are many possibilities what things could have evolved and even more possibilities how they could have evolved.

The fact that Microsoft bought Q-DOS at one moment is a part of the history of operating systems, but this fact was not really necessary for the actual evolution of MS Windows that followed afterwards. In the same way, the species were evolved after many events that occured within billions of years - but almost neither of them was absolutely necessary for the currently seen species to be evolved. Because the available datasets about the history of the Earth are limited - which is an inevitable consequence of various laws of Nature - it is simply impossible to reconstruct the unique history in many cases. However, it is possible in many other cases and people are getting better.

• (4) Why in the world should we think that such mechanisms provide the right answer?

Because of many reasons. First of all, we actually observe the biological mechanisms and related mechanisms - not only in biology. They take place in the world around us. We can observe evolution "in real time". We observe mutations, we observe natural selection, we observe technological progress driven by competition, we observe all types of processes that are needed for evolution to work. Their existence is often a fact that can't really be denied.

Also, we observe many universal features of the organisms, especially the DNA molecules, proteins, and many other omnipresent entities. Sometimes we even observe detailed properties of the organisms that are predicted by evolution. Moreover, the processes mentioned above seem to be sufficient to describe the evolution of life, at least in its broad patterns. Occam's razor dictates us that we should not invent new things - and miracles - unless they become necessary. Moreover, evolution of life from simple forms seems to be necessary. We know that the Universe has been around for 13.7 billion years and the Earth was created about 5 billion years ago. We know that this can happen. We observe the evolution of more complex forms in the case of chips and in other cases, too.

According to the known physical laws and the picture of cosmology, the Earth was created without any life on it. Science must always prefer the explanations that use a minimal amount of miracles, a minimal set of arbitrary assumptions and parameters, and where the final state looks like the most likely consequence of the assumptions. This feature of science was important in most of the scientific and technological developments and we are just applying the same successful concepts to our reasoning about everything in the world, including the origin of species.

In this sense, I agree with William Dembski when he says that science rejects the creation by an unaccessible and unanalyzable Creator a priori. Rejecting explanations based on miracles that can be neither analyzed nor falsified is indeed a defining feature of science, and if William Dembski finds it too materialistic, that's too bad but this is how science has worked since the first moment when the totalitarian power of the Church over science was eliminated.

• (5) And why shouldn’t we think that there is real intelligent engineering involved here, way beyond anything we are capable of?

Because of the very same reasons as in (4). Assuming the existence of pre-existing intelligent engineering is an unnatural and highly unlikely assumption with an extremely small explanatory power. One of the fascinating properties of science as well as the real world is that simple beginnings may evolve into impressive outcomes, and modest assumptions are sufficient for us to derive great and accurate conclusions. The idea that there was a fascinating intelligent engineer - and the result of thousands or billions of years of his or her work is an intellectually weak creationist blog - looks like the same development backwards: weak conclusions derived from very strong and unlikely assumptions; poor future evolved from a magnificent past. Such a situation is simply just the opposite of what we are looking for in science - and not only in science - which is why we consider the opinion hiding in the "question" number (5) to be an unscientific preconception. (The last word of the previous sentence has been softened.)

We don't learn anything by assuming that everything has to be the way it is because of the intent of a perfect pre-engineer. We used to believe such things before the humans became capable to live with some degree of confidence and before science was born. Today, the world is very different. For billions of years, it was up to the "lower layers" of Nature to engineer progress. For millions of years, monkeys and humans were mostly passive players in this magnificent game.

More recently, however, humans started to contribute to the progress themselves. Nature has found a new way how to make the progress more efficient and faster - through the humans themselves. Many details are very new but many basic principles underlying these developments remain unchanged. Science and technology is an important part of this exciting story. They can only solve their tasks if they are done properly. Rejecting sloppy thinking and unjustified preconceptions is needed to achieve these goals.

Incidentally, Inquisition and censorship works 100% on "Uncommon Descent". Whoever will be able to post a link on Dembski's blog pointing to this article will be a winner of a small competition. ;-)

Technical note: there are some problems with the Haloscan "fast comments", so please be patient. Right-clicking the window offers you to go "Back" which you may find useful.

String theory is phrase #7

The non-profit organization

• Global Language Monitor

located in San Diego, CA, has released its top word list for 2005 (news). The top words are led by "refugee" and "tsunami". Names are led by "God", "tsunami", "Katrina", and "John Paul II". Included are also musical terms and youthspeak.

The top seven phrases are the following:

• out of the mainstream
• bird flu
• politically correct
• North/South divide
• purple thumb
• climate change and global warming
• string theory

You see that almost all of the words and things that The Reference Frame dislikes are above string theory. The defeat of string theory by the global warming is particularly embarassing. ;-) But the 7th place is not so bad after all.

Concerning political correctness, it is just not the phrase itself that was successful. Many new political correct words were successful, too. For example, the word "failure" was replaced by "deferred success" in Great Britain. On the other hand, the politically incorrect word "refugee" - that many people wanted to replace with "evacuee" - was a winner, too.

Incidentally, Jim Simons, after having discovered Chern-Simons theory and earned billions of dollars from his hedge fun(d), wants to investigate autism.

Sustainability

Roy Spencer has a nice essay on sustainability in TCS daily. The only sustainable thing is change, he says. He also argues that if the consumption of oil or production of carbon dioxide were unsustainable, a slower rate of the same processes would be unsustainable, too.

Sustainability becomes irrelevant because of technological advances in almost all cases. Spencer chooses Michael Crichton's favorite example - the unsustainable amount of horseshit in New York City 100 years ago when there were 175,000 horses in the city. Its growth looked like a looming disaster but it was stopped because of cars that suddenly appeared.

Also, he notices that the employees of a British Centre for Ecology and Hydrology - that had to be abolished - were informed that the center was unsustainable which is a very entertaining explanation for these people who fought for sustainability in their concerned scientific work. Also, Spencer gives economical explanations to various social phenomena. For example, the amount of possible catastrophic links between our acts and natural events as well as the number of types of our activities that will be claimed to be "unsustainable" in the scientific literature is proportional to the amount of money we pay to this sector of science.

It looks like we can run out of oil soon because the companies have no interest to look for more oil than what is needed right now - it is expensive to look for oil. That makes it almost certain that we will find much more oil than we know today.

Pure heterotic MSSM

As announced in October here, Braun, He, Ovrut, and Pantev have finally found an exact MSSM constructed from heterotic string theory on a specific Calabi-Yau.

• Exact MSSM

The model has the Standard Model group plus the U(1)_B-L, three generations of quarks and leptons including the right-handed neutrino, and exactly one pair of Higgs doublets which is the right matter content to obtain gauge coupling unification.

By choosing a better gauge bundle - with some novel tricks involving the ideal sheaves - they got rid of the second Higgs doublet. While they use the same Calabi-Yau space with h¹¹=h¹²=3 i.e. with 6 complex geometric moduli, they now only have 13 (instead of 19) complex bundle moduli.

The probability that this model describes reality is roughly 10⁴⁵⁰ times bigger than the probability for a generic flux vacuum, for example the vacua that Prof. Susskind uses in his anthropic interview in New Scientist. ;-)

Something between 2 and 3 billion visitors

This is how you can make quarter a million sound like a lot. ;-)

There is a counter on the right side. If you happen to see the number 250,000, you may write your name as a comment here. The prize for the round visitor includes 3 articles that he or she can post here.

The number 250,000 counts unique visitors - in the sense that every day, one IP address can only increase the number by one. The total number of hits is close to 1 million.

The Reference Frame does not plan any further celebrations. ;-)

Update: Robert Helling and Matt B. both claim to have grabbed 250,000, and I still have not decided who is right. Matt B. has sent me a screenshot so his case is pretty strong. It is academically possible that the number 250,000 was shown to two people - because by reloading, one can see the current "score" without adding a hit.

Lisa's public lecture

I just returned from a public lecture of Lisa Randall - who promoted science of extra dimensions and her book Warped Passages - and it was a very nice and impressive experience. Not surprisingly, the room was crowded - as crowded as it was during a lecture of Steve Pinker I attended some time ago. As far as I can say today, she is a very good speaker. There was nothing in her talk that I would object to and nothing that should have been said completely differently.

As you can guess, I was partially feeling as a co-coach whose athlete has already learned everything she should have learned. ;-)

Nima Arkani-Hamed introduced Lisa in a very professional and entertaining way. Randall used a PowerPoint presentation, showed two minutes of a cartoon edition of Abbott's Flatland, explained what are different ways to include and hide extra dimensions (with a focus on warped geometry), how they are related to some of the problems of particle physics such as the hierarchy problem, how do they fit into the framework of string theory and what string theory is, and what are the methods with which we're possibly gonna observe them. After the talk, she answered many questions from the audience in a completely meaningful way.

What is expected that the visitors of this blog will discuss are the interactions between the laymen and the scientists. The questions were not totally bad, I've heard much worse questions in my life - but still, most of the laymen's questions after such public talks are not too deep. Many of them show a rudimentary misunderstanding of some basic principles of science; of the way how physics operates, and so forth.

For example, one Gentleman asked the following question: I've seen a program on NOVA where a physicist proposed that particles were like pieces of rubber band, and the referee rejected the paper. What will happen if the referee was right after all? The Gentleman apparently expected some kind of nuclear war.

Of course, some of these questions may be annoying for a speaker. After one hour of explaining different ways how the extra dimensions are hidden, someone else asked why don't we see them. Lisa did not become upset in any way, and patiently attempted to answer the question again. Another question more or less started from the assumption that relativity and quantum mechanics make all things subjective and dependent on the psychology of individual observers - and the lady asked how do the extra dimensions confirm the paradigm. ;-)

This was definitely not the first time when the laypersons ask exactly the same "question", and my feeling is that even Lisa had already faced it before. She knew what to say.

The laymen's questions following similar lectures also follow a certain pattern. It is a slightly different pattern than the approach of the crackpots who like to show their opinions about science on the internet. There are also some similarities. Nevertheless, the laypersons who attend the public talks are much more influenced by the TV programs and by the general culture.

Coldest December

My time for writing on the blog continues to be limited, so let me just offer you a short provocation. The scientists may have been right after all, the global cooling is coming. ;-) This December will almost surely become one of the coldest American Decembers since the 19th century. Daily record lows have been breached in New York State (10 degrees F below the previous record), the Midwest (Illinois), Utah, Texas (classes canceled), Oklahoma, Colorado, Kansas, Pennsylvania (previous record was 1958), and elsewhere. More snow and cold is forecast. Natural gas is propelled to record.

You may say that it is just the U.S. However, severe cold wave grips North India, too, with at least 21 casualties. The capital sees the coldest day in 6 years. The same thing applies to China and the Communist Party of China helps poor to survive bitter winter. You may complain that I only talk about countries that host one half of the world's population. You're right: the global temperature continues to be stable, around 2.7 Kelvins. ;-)

We are doing fine in Massachusetts, the temperature is -10 Celsius degrees with windchill at -18 Celsius degrees. Tonight, it will be around 6 Fahrenheit. Don't forget your sweaters and gloves.

The consensus scientists have may found a sign error in their calculations. The carbon dioxide causes global cooling. This occassional sign flip is called the climate change.

Shut up and calculate

I would not promote overly technical lecture notes, especially not about things covered in many books. But the interpretation of quantum mechanics in general and decoherence in particular - a subject that belongs both to physics as well as advanced philosophy - is usually not given a sufficient amount of space in the textbooks, and some people may be interested in Lecture23.pdf.

Riemann's hypothesis

I just received a lot of interesting snail mail. The first one is from Prof. Winterberg, one of the discoverers of cold fusion. He argues against the extra dimensions, using a picture of naked fat people (actually, some of them are M2-branes) and a German letter he received from his adviser, Werner Heisenberg. Very interesting but I apologize to Prof. Winterberg - too busy to do something with his nice mail and the attached paper.

A publisher wants to sell the 1912 manuscript of Einstein about special relativity. Another publisher offers books about the Manhattan project and Feynman's impressive thesis.

One of the reasons I am busy now is Riemann's hypothesis. Would you believe that a proof may possibly follow from string theory? I am afraid I can't tell you details right now. It's not the first time when I am excited about a possible proof like that. After some time, I always realize how stupid I am and how other people have tried very similar things. The first time I was attracted to Riemann's hypothesis, roughly 12 years ago, I re-discovered a relation between zeta(s) and zeta(1-s). That was too elementary an insight that was far from a proof but at least it started to be clear why the hypothesis "should be" true. The time I need to figure out that these ideas are either wrong or old and standard is increasing with every new attempt - and the attempts become increasingly similar to other attempts of mathematicians who try various methods. Will the time diverge this time? :-)

Arthur Jaffe indicates that he believes that he does not think that anyone can prove it, maybe except for Alain Connes, because it has not been proved for 150 years despite many attempts of ingenious people and it can't be proved now by mathematical induction either. ;-) I beg to differ. There are many new insights that were unknown to the great mathematicians in the past, and the problem simply can be cracked at some moment. The zeta function and primes have appeared in p-adic string theory but this research direction was always something like a collection of identities than an actual theory whose physics could imply important insights. The new approach may be more promising.

52.3 percent growth

What is a reasonable size of the GDP growth? 10 percent like in China? 4 percent like in the U.S.? Around 1 percent like in many European countries?

What if I tell you that a particular country had the GDP growth of 52.3 percent in 2004? Moreover, it is a country that is usually described as such a failure that the president of another country who more or less caused all these developments, including the number 52.3, should be hated or maybe even impeached according to hundreds of thousands of activists?

Don't you think that something is crazy about this whole situation? The country has not only a terrific growth potential but also a big potential to become an extremely civilized territory, just like it was thousands of years ago when Europe was their barbarian borderland.

Whether or not these things will happen depends on the acts of many people. Especially the people in that country itself. And also the people from other places in the world, especially America. Who do you think is a better human? Someone who tries to support positive developments in the world, including the country above, or someone who dreams about a failure in that country that would confirm his or her misconceptions that the president is a bad president?

I, for one, think that the members of the second group are immoral bastards. Moreover, it is pretty clear that most of them will spend the eternity at the dumping ground of history, unlike the president who will be written down as an important U.S. president in the future history textbooks.

All those critics who still retain at least a flavor of some moral values: please stop your sabotage as soon as possible. Even if you achieve what you want - a failure - it will be clear to everyone that the failure is not Bush's fault but your fault.

Observables

The word "observable" is a fancy term for any feature of the physical objects that can be measured or otherwise observed. An "observable" is anything whose value is shown by any apparatus you may imagine. Various simple and complicated gadgets can translate one type of observable into another one and inform us about reality.

Because this very general definition, it should be clear that physics cannot be done without observables. Any theory that should be evaluated scientifically must have some observables and these observables are more directly or less directly compared with the outcomes of experiments.

There are only two known frameworks in physics how observables are computed, how they evolve in time, and how they are intepreted and compared with measurements. The two frameworks are

• classical physics
• quantum mechanics

The first one occurs as a special case of the second one. And the second one, quantum mechanics, is how the real world works. Everything indicates that there exists no other interpretation of the observables that could be, at least remotely, compatible with the qualitative features of the real, quantum world.

The word "observable" only became popular when quantum mechanics started to dominate.

In classical physics, observables are the basic degrees of freedom - such as coordinates and momenta of particles and/or values of the electric and magnetic fields at various points - or any functions of these variables - such as the angular momentum or the energy density integrated over the Solar system.

One of the postulates of quantum mechanics is that these observables are upgraded to operators on a Hilbert space. It is the eigenvalues of these operators that are measured, and the probability of various outcomes is determined as the absolute value of a certain complex amplitude squared. In ordinary non-gravitational quantum systems, we can typically define a concept of time and the complex amplitudes (the wavefunction) evolve according to the Schrödinger equation. The wavefunction itself is not an observable; it is not an operator and moreover its values are not directly measurable. The previous sentence is partially deep and partially an irrelevant piece of terminology.

Equivalently, the complex amplitudes may be directly calculated using Feynman's path integral. Equivalently, the wavefunction may be kept constant and the operators evolve in time - this is how it works in the Heisenberg picture. It differs from the Schrödinger picture much like two differently rotating systems of coordinates differ from one another.

In field theory, the number of independent observables becomes infinite: in each point of spacetime, we find an observable. This fact is true both in classical field theory as well as quantum field theory. Nevertheless, the principles are qualitatively unchanged. Although the number of observables is infinite, they follow very much the same rules as in ordinary classical or quantum mechanics. There are some technical issues involving distributions, divergences, regularization, renormalization etc., but they do not change the basic setup.

Observables in quantum gravity

Things are very different if general relativity because there is no longer a preferred definition of time. You may say that the same thing was already true in systems that respected special relativity. Yes, these systems have many notions of time related by Lorentz transformations but each of them may be adopted to give us the same kind of time-evolution as we had in non-relativistic physics.

However, this is not the case in general relativity. Why? It is because the set of different choices of the time coordinate forms an infinite-dimensional space. The symmetry that relates these different descriptions is a local symmetry - analogous to gauge symmetries in Yang-Mills theory - namely the group of diffeomorphisms. In classical physics, we know exactly what we are doing: general relativity allows us to calculate the metrics as long as we realize that the coordinates are not directly physical because they can be redefined in an arbitrary way.

In quantum mechanics, general relativity becomes more subtle. It is because the physical states must be invariant under gauge symmetries. The diffeomorphism transformations mentioned above also include time translations. This seems to imply that the wavefunction is time-independent as long as we compute the time-dependence with all the required terms. The fact that the overall generator of time translations "H" annihilates the full wavefunction is known as the Wheeler-deWitt equation.

You may think that this is a complete disaster because the state of the Universe is surely not time-independent. Well, it is not a complete disaster. It is because the diffeomorphisms that change the asymptotic structure of spacetime do not have to keep the wavefunction invariant. Only the diffeomorphisms that mostly act "inside the spacetime" have to keep the wavefunction invariant. Because the other diffeomorphisms may change the wavefunction, the wavefunction is allowed to have a nonzero ADM energy and similar features. These observables are calculated from the behavior of the metric and other fields at infinity.

Well, if there is some infinity.

In the Minkowski space and de Sitter space, we can safely define the energies according to the strategy above, and we may also determine the time evolution, but only from -infinity to +infinity. If these infinities really appear in the far past and the far future, we call the evolution operator "S-matrix". String theory allows us to calculate the S-matrix (another example that we do call an "observable") for all particles in the spectrum which includes the scattering of gravitons. We don't have to insert our knowledge about the problematic "bulk" observables: string theory automatically tells us not only the right answers but also the right questions. "It is the S-matrix you should calculate, silly," she says. It also tells us what are the corresponding evolution observables for anti de Sitter space.

Someone may therefore convince you that the S-matrix is the only meaningful observable that has any physical meaning in a quantum theory of gravity. This sentence is both deep, if an appropriate interpretation is adopted, as well as discouraging.

It is deep because we know that the local Green's functions or other local objects that are calculable in quantum field theories do not have a well-defined meaning in quantum gravity as long as they are nicely "covariant". And it is also deep because the S-matrix actually contains a lot. If we study particle scattering, the interaction region is typically so much smaller than our detectors that the interior of the detector may be approximated by an infinite spacetime, and the S-matrix contains all measurable information about the system. Even if we study more messy systems, the S-matrix actually knows a lot about physics, including the low-energy effective theory, and these insights may be combined with other pictures to determine the behavior of "less empty" configurations of matter, too.

On the other hand, such an S-matrix picture is almost certainly inappropriate for early cosmology. The very beginning of the Universe is not described by an S-matrix, at least not the type of S-matrix we know. When the Universe was small, the S-matrix was still useless. How do we deal with these problems?

One of the obvious remedies to get rid of the negative consequences of the local diffeomorphism group is to gauge-fix it. For example, you can go to the light-cone gauge. String theory in the Minkowski backgrounds may also be written in the light cone gauge. The result is that after such a gauge-fixing, the theory effectively becomes an ordinary theory analogous to the non-gravitational quantum field theories and one can ask the local questions and the questions what happens when the system evolves by a finite time interval. In reality, we rarely ask such questions - and even in the light-cone gauge, we continue to compute primarily the S-matrix - but in principle, you could ask these questions.

However, the light-cone gauge is also highly inappropriate for the context of cosmology, the creation of the Universe, and its early moments - because it relies on the existence of a null Killing vector that definitely disappears near the Big Bang. What can you do? Maybe we should look for other types of gauge-fixing that are more appropriate for approximately homogeneous and isotropic backgrounds that change rapidly with time. It's almost guaranteed that these other types of gauge-fixing will be more messy.

The loop quantum gravity people would offer you entirely different observables, such as the areas of two-dimensional surfaces in space. I am convinced that all these things are completely unphysical. Some speculations about the discrete spectrum of the areas, even if they were right - which I am equally sure is not the case - would be completely disconnected from the cosmic microwave background, distribution of galaxies, or any other indirect observation of the early Universe that we have done - and probably any observation that we will ever do. It's just not physics. Well, so far my statement seems completely obvious because the notions of loop quantum gravity seem to be disconnected from anything that looks like space in the first place. ;-)

Should we care about the problems?

You see that there are great difficulties to go from geometries with a nice behavior at infinity - such as the Minkowski and AdS spaces - to geometries without such a nice behavior, such as compact topologies in cosmology. Should we care about these problems?

My answer to this question is mixed. I am sure that we should eventually describe the early cosmology in a quantum language - because these events definitely have had observable consequences. On the other hand, my feeling is that almost everything that has been speculated about these non-asymptotic observables in quantum gravity has been largerly physically irrelevant.

As discussed above, a great deal of the local behavior is encoded in the S-matrix. Also, one can typically write down a coupled system involving a classical background metric and other quantum fields propagating in this background. Non-gravitational quantum field theory defined in a curved background is a pretty well-established framework that does not differ much from regular quantum field theory on flat backgrounds. And classical general relativity is well-established, too. And this combination continues to be sufficient for many questions.

However, it is not quantum gravity and it is guaranteed to break down when the quantum effects start to play a big role for gravity. The previous approximative picture definitely breaks down when the Universe is 1 Planck time from the Big Bang. And it probably gives misleading predictions for the GUT-scale inflation and other things, too.

Ignorance about the early Universe

There are several types of insights about the early Universe that we do not know yet.

I am talking about the early Universe because I am aware of no evidence that would support the idea of a big pre-history prior to the Big Bang or the statements that such a pre-history added to our picture of the Universe explains something or is scientifically natural or inevitable. This is why I apply Occam's razor to these ideas. Of course, eventually, we may revise them again if there is some evidence.

Some of them are related to our typical problem with the vacuum selection. Just like we don't know which "Standard-like Model" in the broad selection offered by string/M-theory is the right one, we also do not know which "generalized inflationary model" is the right one. These two things come in the same package. Of course that if we localized the correct place in the "landscape", we would probably answer all of these questions simultaneously.

Inflation destroys most of the information about the initial conditions of the Universe at the beginning of the inflation (or before it). That's a good thing because it makes much of our ignorance irrelevant. But you may still wonder that some general features of these initial conditions won't be inflated away; the choice of the compactification is an obvious example. The initial conditions are likely to remain something that influences our Universe and our current observations, and should therefore be a topic addressed by physics sometime in the future. The framework of the Hartle-Hawking wavefunction remains the only set of rules that makes some sense to me in this respect, and there remain questions how to embed it in string theory.

There have been many speculations about "solving the problems" with the Big Bang that avoided the concept of the Hartle-Hawking wavefunction. Neither of these speculations make sense to me, as far as I remember. Why? Because neither of them says that the initial conditions are unique and what they are. In fact, the word "unique" is far too strong. These speculations in fact do not impose any constraints on the initial conditions whatsoever. They typically say that they can define "nice" theory but this theory treats all conceivable initial conditions on par. From a physical perspective, this is exactly equivalent to having a singularity where everything becomes unpredictable.

Occam's razor dictates that we should imagine that the Universe starts at time "T" with the initial conditions that lead to a Universe that matches the observations and you should try to make "T" as small as possible given the constraint that your initial conditions will remain natural. In other words, we should never try to imagine that we describe an epoch before "T" unless our new description makes the whole picture more reasonable and its predictions more likely and natural. In other words, we should not pretend that we understand something even though we can't say anything new about it.

The only reason why the physicists may be interested in the very early Universe, its initial conditions, and a theory that describes that is that these conditions influence observations that we can do today and in the future - and the only role of the theory is to tell us something about these observations. This is only possible if the initial conditions are unique or at least heavily constrained, and if a quantum theory of the Big Bang does not offer us any constraints of this kind - and, instead, it tells us that "anything goes" - its value for physics is exactly equal to zero.

There seems to be some virtual reality in the investigation of various causally convoluted black hole geometries etc. As far as I am concerned, the four-dimensional black holes of the usual types (Schwarzschild, Reissner-Nordström, Kerr, Kerr-Newman) are the only ones that are relevant for physics. Sometimes we have problems to convince some of our colleagues even about this modest statement, but that's a different issue.

All other black holes we theoretically encounter are toy models that are only relevant for natural science if they share their qualitative features with the observed black holes. Most of the time, it is easier to calculate supersymmetric black holes in various spacetime dimensions etc. because it is more mathematically elegant and controllable. And of course, mathematical elegance and new relations between mathematical objects is a great thing, too. But the results are physically relevant only if they have some counterpart in the world of observable physics and if we can actually argue that they are in the same "universality class". It has been absolutely great to learn that the quantum picture of the black holes is internally consistent. But a huge amount of new insights about unphysical configurations in gravity has been developed - a much bigger amount than what we will ever be able to observe.

This fact makes it harder that these insights are "physics" in the most conventional sense. They are "physics" as understood by string theory - which also includes all other configurations in all other backgrounds allowed by string theory. And in some speculative cases, it also includes configurations that are not guaranteed to be allowed by string theory once it's properly understood. Well, it's a hard task to find something that is directly relevant for some unexplained observations because there are almost no unexplained observations available.

But this situation should not obscure the difference between physics - that always needs observables - and philosophy that can do without them. As a well-known cosmologist said, physics depends on the fine balance between cold and boring experimental data and hot and exciting theoretical speculations. Whenever this balance is lost, physics degenerates either to botanics or to philosophy. ;-)

In some sense, this observation has its counterpart in high-energy theoretical physics. In the long run, high-energy theoretical physics depends on the fine balance between the bottom-up approach and the top-down approach. If the balance is broken, high-energy theoretical physics either degenerates into phenomenology (in the insulting sense) that only describes what we already know and that makes new correct predictions purely by chance; or it degenerates into philosophy or religion that uses string theory as a captive.

Magnetic poles drifting

The drifting of Earth's magnetic poles has accelerated. In 1831, the North magnetic pole was observed for the first time. It was found that by 1904, it moved 50 kilometers to the North. However, since that time, it has been displaced by 1,000 kilometers! And the process is accelerating. Auroras will be exported from Alaska to Siberia (or Europe) in 50 years which is quite natural because St. Petersburg is, after all, the most appropriate place for all Auroras.

The strength of the magnetic field has decreased, too: the difference is about 10 percent in the last 150 years.

Surely, such dramatic dynamics must be of anthropogenic origin, the anti-capitalist and anti-civilization fanatics will eventually say. An evil corporation has surely ordered 10^{24} kilograms of iron to move in a visibly different direction. The only detail to figure out is which industry is responsible, order the "scientists" to write papers that prove the link using the methods of scientific consensus, and initiate the magnetic Kyoto protocols that will save the Earth's magnetic field.

I guess that the evil industry that is destroying the geomagnetic field may be the commercial software industry, especially Microsoft. By avoiding the open source standards, the companies make the electrons inside transistors of hundreds of millions of computers in the world pointing in the same direction which weakens the magnetic field of Mother Nature. ;-)

Radicals going after Lieberman

Joe Lieberman has always been one of my favorite politicians. Unfortunately, he had chosen a political party that is somewhat ironically called "Democratic Party". In relation to Iraq, Lieberman believes the very same principles as every other sane person. Right now, it is very important for Iraq to become a safe and democratic country. It is equally important for the emerging democracy and those who support it to defeat the local terrorists. In the U.S. context, this of course means that one should be supportive of the White House, at least in the broad patterns, regardless of his or her political affiliation.

The previous sentences are obvious, nevertheless they are apparently "politically incorrect" at many corners of the "Democratic Party".

• NYT about Lieberman

The New York Times inform that a group led by James Dean, the brother of the DNC chairman Howard Dean, has collected 30,000 signatures of confused people and they will send the critical letter to Joe Lieberman. The obnoxious communist movement moveon.org claims that they will try to replace the popular senator of Connecticut at the polls - which, of course, does not sound terribly realistic. At any rate, I would call these things intimidation.

This intimidation is not only wrong. It also shows a deep misunderstanding of the political facts. Joe Lieberman was, together with John McCain, a co-author of a bill that has made overthrow of Saddam Hussain an official U.S. policy in 1998. I wonder why do the "Democrats" exactly think that Lieberman would suddenly start to follow their "official" dumb anti-war ideology whose only purpose is to create new problems for George W. Bush and for all of us. In reality, Lieberman has historically been more connected with the hawkish attitude towards Hussain's regime than George W. Bush himself.

More generally, it is also nonsense to argue that the tradition of the Democratic Party would justify an official anti-war stance of all members. It was the Democratic Party administrations that have involved the U.S. in virtually all big wars of the 20th century. The First World War, the Second World War, Vietnam, and Kosovo are examples. Clinton also started the Desert Fox in 1998, being convinced that Iraq had WMDs. Almost everyone whose opinion mattered was convinced it was the case. Madlenka Albright was as hawkish as Donald Rumsfeld; see for example this page. The Bush administration simply inherited a system of policies and opinions and acted in this framework.

Lieberman would be one of the most natural Democratic candidates for President in 2008 but I am afraid that there are too many loud, far left-wing lunatics within his party who will make it impossible.

Nobel lectures

Those who are interested in the newest winners of the physics Nobel prize may also want to see yesterday's Nobel lectures. Roy Glauber's lecture has a slightly historical character - 100 years of light quanta. His laser physics co-winners talk about the Passion for precision and Defining the optical frequencies.

Snowstorm

This year, snow started before the Halloween - but the weather we see today deserves the title "snowstorm" for the first time. It is pretty. Narayan K. has tried to leave Boston in the morning. Hirosi Ooguri has another flight to L.A. tonight. Both of them are at risk. Although the snow is rather heavy, it is forecast that most of the snow will disappear during the weekend.

Utter confusion

David Gross has not only organized the prestigious Solvay conference but he also summarized it by the following words published in one article and second article in New Scientist:

• We don't know what we're talking about
• We are much like the physicists in 1911 who did not understand radioactivity
• We are missing perhaps something as profound as they were back then
• The field is in a period of utter confusion

These words are slightly uncharacteristic for one of the greatest optimists among theoretical physicists but on the other hand, they are expected from a great physicist who also knows very well how to criticize. ;-)

The word "confusion" was also used by another leading theoretical physicist in a private debate with me. Be sure that these two gentlemen are not complete dissidents. Well, there have probably been many things going on that do not make much sense. Many things that do not make sense to me. Many things that they do not make sense to the big shots. And I am afraid that the percentage is too sensitive a number for me to estimate it here.

One should however exaggerate neither the importance of one confusing conference nor the importance of one or a couple of discouraging years in the search for something that may be with us for centuries. David Gross has also given a summary of the 1938 Warsaw conference which was very entertaining. These big guys really did not know what they were talking about - except for Klein, of course. (Those who speak German know very well that Gross has all the rights to judge Klein.)

We are certainly in a much better shape today. Nevertheless, the people in the year XY will definitely be humiliating the 2005 Solvay conference, too - because they will know the fundamental insights that we are missing today. It remains our task to try to make the number XY as small as possible.

Peter Woit celebrates the words about the trouble, in a way that resembles the jihadists' celebrations of the Private Katrina, here. ;-) Nowadays, it has become extremely fashionable to criticize string theory and physics beyond the Standard Model in general.

I would like to emphasize that while we are in a period of utter confusion about several questions at the cutting edge, we are not too confused about many other fundamental insights - some of which are newer than 5 years - and we are not confused at all about thousands of other things. Think twice before you replace the whole community of confused physicists - because confusion is the natural state of the theoretical physicist throughout most of his or her life.

You may start with physicists who are confused whether XY may become a solution of the cosmological constant - but if you promote real "diversity of approaches", you may end up with a general confusion about the difference between a force and voltage.

Lenny's book is out

Amazon.com will start to sell Lenny Susskind's book on Monday but you may be able to find it in your favorite bookstore right now. I've seen the first chapter and it is very poetic, slightly more mysterious than expected, but otherwise matching expectations. Peter Woit is looking at his book from his own, characteristically destructive viewpoint. We have discussed the review at TechCentralStation and George Ellis has another one in Nature.

Is electricity fire?

This text is not a real article, just an annotated link to

• Roy Spencer's article

at TechCentralStation about the cultural shock that the author experienced in Montreal as a scientist among, well, scientific ignorants. His description seems extremely similar to the story "Is electricity fire?" in Feynman's classic book

• Surely you're joking, Mr. Feynman

Spencer was surrounded by thousands of people who were not interested in actual numbers, calculations of uncertainties, or error margins. People who had no idea how the economy or the real world works. The only way why these people would ever be interested in science was that they wanted to interpret their ancient, provincial, medieval religious dogmas - such as the stupid dogma that what is good for the economy must be bad for the Earth, much like the rabbinistic students who asked Feynman "Is electricity fire?" not because they were interested in science but because they needed to know whether Talmud allowed them to use the elevator on Saturday although it forbids fire on the same day.

Now imagine thousands of people in Montreal complaining about the urgent threat of global warming that required action "now" - when the temperature outside is 16 Fahrenheit. People whose whole careers depend on the wealth of the modern civilization and who consume food and electricity for very many millions of dollars (and, less importantly, who also produce a lot of CO2 during their gathering). The only result that these pompous fools have is that all of them describe the only real scientists at the conference as "Flat-Earthers".

And our society is funding this idiocy. Is not it sad?

Concerning their misunderstanding of economics, we can find a similar example in the same section of Feynman's book.

• There was a special dinner at some point, and the head of the theology place, a very nice, very Jewish man, gave a speech. It was a good speech, and he was a very good speaker, so while it sounds crazy now, when I'm telling about it, at that time his main idea sounded completely obvious and true. He talked about the big differences in the welfare of various countries, which cause jealousy, which leads to conflict, and now that we have atomic weapons, any war and we're doomed, so therefore the right way out is to strive for peace by making sure there are no great differences from place to place, and since we have so much in the United States, we should give up nearly everything to the other countries until we're all even. Everybody was listening to this, and we were all full of sacrificial feeling, and all thinking we ought to do this. But I came back to my senses on the way home.
• The next day one of the guys in our group said, "I think that speech last night was so good that we should all endorse it, and it should be the summary of our conference."
• I started to say that the idea of distributing everything evenly is based on a theory that there's only X amount of stuff in the world, that somehow we took it away from the poorer countries in the first place, and therefore we should give it back to them. But this theory doesn't take into account the real reason for the differences between countries -- that is, the development of new techniques for growing food, the development of machinery to grow food and to do other things, and the fact that all this machinery requires the concentration of capital. It isn't the stuff, but the power to make the stuff, that is important. But I realize now that these people were not in science; they didn't understand it. They didn't understand technology; they didn't understand their time.
• The conference made me so nervous that a girl I knew in New York had to calm me down. "Look," she said, "you're shaking! You've gone absolutely nuts! Just take it easy, and don't take it so seriously. ..."

Well, Feynman was obviously not the only one who had similar reactions to these pompous fools who don't understand science, economics, and the real world. However, he did not have a blog so that he only encountered their moronic comments a few times in his life, not every day as your humble correspondent. ;-)

Roy Spencer attempts to define the basic principles of economics that should be taught before the end of the high school here.

Electric dipole moments

Adam Ritz (CERN & Victoria) just gave a talk about the electric dipole moments of elementary particles and their constraints on new physics.

Do elementary particles have a dipole moment? Something analogous to two opposite charges separated by a distance? A dipole moment is a vector, and by rotational symmetry, the only direction that the dipole could take is the direction of the spin.

A special comment for Quantoken. By elementary particles, I mean leptons, quarks and gauge bosons (and possible the Higgs and graviton) - and their simple enough bound states that have no particle physics reason to have a significant (=beyond the CKM contribution) dipole moment, such as the neutron. More complicated structures such as molecules of course usually have a dipole moment whose origin we understand very well. That's also the case of some atomic states where the dipole arises from various relativistic corrections.

You know that the magnetic moment of a particle is always proportional to the spin with a fixed coefficient that depends on the particle type only. So if the particles also have an electric dipole, then there is some correlation between the electric moment and the magnetic moment. But which sign should this relative factor have? You know that E is a vector but B is a pseudovector, and therefore the electric dipole moments of the particles violate P (parity) much like CP (parity combined with charge conjugation).

The Standard Model predicts certain small electric dipole moments of particles such as neutron - because of the CP-violating phases in the CKM matrix used for quark masses. New theories of physics including supersymmetry typically predict more significant violations of the CP symmetry which also means significant dipole moments.

Experiments try to measure the dipole moments in various types of materials - liquid Xenon is a crazy example. No dipole moments of the elementary particles have been found so far which puts strong constraints on the parameters of new theories such as MSSM (minimal supersymmetric Standard Model) as well as baryogenesis (but no constraints on leptogenesis).

Various other experiments are underway and some of them are being prepared. One of them may cost as much as 10 million dollars, if you want to have an idea about the budget. Many of them want to access the limit

• d = 10^{-29} electron.centimeter

where "electron.centimeter" is a natural unit of the dipole moment. It is the same dipole as an electron-positron pair separated by 1 centimeter. You see that the corresponding distance "10^{-29}" centimeters is tiny; it is much shorter than the typical "radius" of the particles. Once the experiments get to this level, the subject of EDMs will be over because this is the scale of the dipole moment predicted by the Standard Model. Well, we should eventually see the basic dipole moments predicted by the Standard Model but it is virtually impossible to measure the EDMs accurately. In other words, it would be impossible to distinguish new contributions from the Standard Model background.

The negative results of the experiments looking for the dipole moments is a bad news for more or less any theory of new physics. No really convincing explanation why the CP violating terms should vanish has been given in the case of supersymmetry. It is also a bad news for the anthropic principle because the unnaturally small values of the dipole moments are apparently not required for any mechanism underlying life.

Of course, it is good news for everyone who is quite happy with the Standard Model. It is even better than we thought.

Instant LaTeX to HTML

That's a singlet (entangled) state. Everyone who creates any kind of HTML pages can include mathematical equations like one above using the following tag:

• <img src="http://shitalshah.com/?$3+3=6$">

where $3+3=6$ is an example of a TeX command. The yellow color above was chosen using the TeX command \yellow and you can guess what are the commands for other colors. Of course, there are ways how can you install the required scripts on your server so that the name of the server http://shitalshah.com/ may be completely omitted. The script is based on MimeTeX and Shital's improvements of it are described and offered here.

Unfortunately, the images cannot be included in the comments at blogs run by blogger.com.

Also, I can't offer you LaTeXrender used by Peter Woit because this blog is not based on the software by WordPress. But it is likely that if I need some mathematical expressions that look really unacceptable in the ASCII format, I will be using Shital Shah's solution instead of the previous plugin.

I don't plan to increase the amount of LaTeX - in whatever format you can think of - on these pages. And I am jealous about the WordPress LaTeXrendering feature.

Update:

AlJazeera argues that only string theory has the right to destroy what God has created.

LaTeX preview

If you need to preview your LaTeX source, you may find the following form useful:

Your LaTeX expression: \Large f(x)=\int_{-\infty}^x e^{-t^2}dt

Now click Submit to see it rendered below:

Moreover, don't forget that if you choose the Siegel gauge, every nontrivial string field theory amplitude contains as part of its expression

• 

This expression was written with the help of a redefined function key F5 that has written the whole HTML command for this expression except for the content in between the two dollar signs. Recommended. ;-) In Debian, I pressed the Windows key, went to the Control center. In Regional/Accessibility, you may choose KHotKeys where you can define new Keyboard input.

Einstein and entanglement

When I was preparing a lecture, I again wondered what would Albert Einstein think today about the interpretation of quantum mechanics if he knew all the experiments that show that his ideas were patently false and that quantum mechanics is absolutely right. Especially the cute experiment described by Mermin - and also by Brian Greene in Chapter 4 of his "The Fabric of the Cosmos".

The world cannot be described by local hidden variables that would act as a "completion" of quantum mechanics, in the sense that Einstein envisioned. Einstein would have a hard time to decide what to think. Either he would abandon his deterministic preconceptions and accept the probabilistic nature of quantum mechanics just like all other serious physicists; or he would continue to think that the world is described by nonlocal hidden variables.

Einstein disliked quantum mechanics but he also disliked nonlocality. I feel that he would finally reject to sacrifice locality - and he would reject to introduce material signals that propagate faster than light. They would be in such a clear contradiction with everything that Einstein believed about locality in space and time and about the local character of the physical law that he could even decide to sacrifice the "objective existence" of some degrees of freedom that describe reality prior to the measurement.

More realistically, I think that Einstein would be saying similar things about the interpretation of quantum mechanics as Prof. Roger Penrose does, and they would also fail to make sense to anyone else. ;-)

More generally, it is an interesting exercise to try to imagine how would Isaac Newton react if someone visited him in the past - or revived him in the present - and showed him the current picture of the world based on quantum mechanics, relativity, and maybe even string theory. I feel that Newton would master all these things very quickly and he would be immensely pleased. And maybe he would not. At any rate, this is an interesting thought experiment that gives us a clue how would the future developments of theoretical physics affect our feelings.

Secret prisons of CIA

There have been claims that CIA is using secret prisons not only in Afghanistan but also in Romania and Northern Poland - and maybe elsewhere - to torture the terror suspects. Both the U.S. as well as the Eastern European countries deny the accusations but it is not hard to imagine that the speculations are correct. There are good reasons to think that they should be correct.

My opinion is the following. This is a war on terror. I don't think that the terrorists deserve the same human rights as the innocent citizens of the democratic countries. Consequently, the comparison with innocent victims of the totalitarian regimes sounds outrageous to me. From a purely moral viewpoint, I think it is appropriate to treat them using the most efficient method that has the potential to disrupt the work of the international terrorist networks - and to indirectly save as many innocent human lives in the future as possible - as long as this method is legal.

Note added later: my sentence has obviously inspired Condi who just said that the US would use "every lawful weapon to defeat these terrorists", and said rendition "takes terrorists out of action and therefore saves lives".

And I admire the U.S. forces for being essentially the only group in NATO that is ready to invest money and effort for the future of the civilization of freedom.

It is my understanding that it is illegal to torture anyone at the U.S. territory, including the terrorists. Also, it is probably illegal for the citizens of most European countries to torture anyone else. Although it may be just a matter of my personal ignorance, I am not aware of similar laws that would prevent CIA from doing such things on the territory of Poland or Romania. And the law is definitely more important for me than the feelings of left-wing critics.

The people in the U.S. military and CIA have a pretty hard job and they face tough enemies. It is impossible to do their job with the naive attitude of the sissy liberals.

The people who have become radical advocates of the human rights of these (mostly) disgusting killers just irritate me - especially because I know very well that they would never do the same thing to defend my rights and the rights (or lives) of many other people I respect. They're just fighting the war on terror on the wrong side - they are primarily fighting against Bush, and they are fighting together with anyone else who is convenient, including Al Qaeda.

I am equally outraged by the assertion of a eurobureaucrat who has threatened Poland, Romania (a prospective EU member), or any other EU country that will be shown to have co-operated with CIA to revoke the country's voting rights in the European Union, among other threats. Can you imagine that? Someone in Poland allows CIA to kick 26 thugs - because he or she thinks, much like me, that it is not such a bad idea - and 30 million of people will lose their voting rights? Is it how the Eurepean supernational democracy is supposed to work?

As far as I know, such a decision would be completely unjustifiable by any existing laws. Also, such a decision would be rather devastating for the trans-Atlantic relations because it would mean that the European countries must be afraid of co-operation with the U.S. forces in any conflict one can imagine. Such a decision would mean that the anti-war fanatics in Europe - and lukewarm friends of Al Qaeda't thugs - suddenly have the right to do completely illegal decisions about whole countries of the EU.

I am sure that such a development would go against the current natural trend. Europe and America are getting closer right now. A female German archaeologist was kidnapped in Iraq which will be another hint for Germany to realize that the relative German passivity does not protect the country from the evil acts of the terrorists. The terrorists fight against the whole Western civilization. Angela Merkel, a physicist and the new German chancellor, probably realizes this fact pretty well. That's just one among many reasons to be optimistic.

The idea that our governments are torturing anyone is not a particularly attractive one; on the other hand, this limited attractivity does not mean that we can really survive without such unattractive acts.

Protests against climate change

Have you ever attended a protest against Newton's gravitational law? A protest against Maxwell's equations? Or a protest against another basic law of Nature? If you have not, you have a great opportunity. Today, the green activists organize worldwide protests against one of these natural laws, namely against the climate change.

The weather and the climate have always been changing at all timescales you can think of. Almost every day, the temperature is higher during the day than what it is at night. Within a couple of days, the average daily temperatures may change by as much as 10 or 20 degrees centigrade. At the annual scale, most people recognize the four seasons. There are 11-year solar sunspot cycles whose relevance for the climate is a matter of debates. Most likely, there are multicentury cycles between climate optimums and little ice ages. Quite certainly, there are multi-millenium Milankovitch cycles whose origin is astronomical in nature. The longest Milankovitch cycles we seem to observe last 100,000 years. If we look at even longer timescales, we will recognize new kinds of glacial periods and different geological eras. At the scale of tens of millions of years, the continental drift becomes essential for a correct analysis of each continent's climate. At the timescale of billions of years, the age of the Sun and the Earth starts to play an important role. I could continue. At the electroweak scale, a fraction of second after the Big Bang, the electroweak symmetry was spontaneously broken as the Universe cooled down below 250 GeV and so forth. ;-)

Many of these factors are very well understood. Many of them have a completely scientific explanation. Others seem rather chaotic, irregular, and unpredictable. I have omitted many other factors that are partially understood - for example volcanoes, asteroids, cosmic rays. There are quite certainly many other cycles and effects that we have not yet observed, identified, and quantified. Some of them will be very predictable. Some of them will look chaotic to us. Many of them will remain chaotic forever and we will always describe them as noise parameterized by a few parameters. At any rate, the lesson is clear. The denial that the climate is naturally changing is fully analogous to the denial that the Earth revolves around the Sun. In fact, the latter is a small subset of the former. Literally.

Freezing protesters against the global warming

But some people just don't want to listen. They're either convinced that the Earth orbitting the Sun is a piece of propaganda of the heretics and the Devil Himself; or they want to believe that the natural climate change is a piece of propaganda created by the evil capitalists. Even if you imagine that your humble correspondent's quantitative ideas about the strength of various effects mentioned above are inaccurate, it must be completely clear to every rational reader that most of the green activists are demonstrably unable to calculate and/or learn the results more accurately.

What drives them is a postmodern perverse kind of religion and political bigotry, not an actual observation or a scientific analysis. Prof. Stott describes the likely goal of their "campaign against the climate change" as follows:

• The organisers of today's 'global warming' marches (see blog below) call themselves, most hubristically some unkind people might say, the 'Campaign Against Climate Change'. Oh me! Oh my! I await eager volunteers to cap volcanoes, to wrestle with the Earth's axis, to dampen down sunspots, to adjust the cosmic ray flux, to divert ocean currents, to MOP (in joke) up water vapour, to re-model the Tibetan High Plateau, to intercept asteroids, to dust the world, and to manage chaos.... among other Herculean tasks.

In the fast comments, the SocialistCommunistEnvironmentalistPig argues that the green brains do not want to stop the physical laws of the climate change and therefore my analogy with Maxwell's equations is not right. Of course that he is absolutely wrong. The sentence "stop climate change" produces around 50,000 hits - from GreenPeace as well as other institutions of a similar type. Of course that they want to "stop the climate change". And it is as mad as trying to stop Maxwell's equations - or trying to set the human contribution to the right-hand side of Maxwell's equations to zero.

(Incidentally, the human production of microwaves - a particular way to evaluate the human term on the right-hand side of Maxwell's equations - is gigantic in comparison with the natural background and much bigger than in the case of the climate. Will the environmentalists also argue that we are the sinners because we change the energy density stored in the microwave spectrum? Shall we replace cellphones by pigeon postmasters?)

BBC explains that the demonstrations have been timed to coincide with a UN summit on climate change in Montreal, Canada. And therefore thousands are marching through the streets of Montreal, Washington, and many cities overseas. In Washington DC, the maximal temperature today is about 3 degrees Celsius although the average maximal daily temperature in DC for December 3rd is about 10 C.

In Montreal, Canada, where the key protests take place, the maximal temperature today is -3 degrees Celsius, with windchill at -11 degrees. Imagine that. It's even more f$&%$* freezing cold outside than what we have here in Cambridge but thousands of people find it completely natural to spend hours in the streets and protest against the global warming.

Of course, they're not the first ones who seem to address the climate but are completely unaffected by any actual data. On January 15th, 2004, the New York City has seen the coldest January 15th since 1957 and the coldest day since 1977: minus two Fahrenheit degrees. Nevertheless, Al Gore has given a major speech about the global warming in New York at exactly the same day.

Of course, he could have afforded it because the people who actually listened to that speech were the same kind of bigots who have no problem to protest against the global warming at the windchill of -11 degrees Celsius. The people who see nothing strange about saying that 0.6 degrees centigrade change of the temperature per century surely cannot be natural - instead, it must be a catastrophic change that was created by the capitalists - but a cold snap that is 20 degrees centigrade below the long-term average is certainly just a fluctuation that can't diminish their excitement from a speech of one of the green prophets, Al Gore.

The right question is not whether a government anywhere in the world should be affected by these bizarre people who attend the protests today and many similar protests. Of course, no responsible government in the world should listen to these lunatics; even BBC agrees that every single participant among those 8,000 green brains is a confused moron. The right question is whether these people are dangerous enough so that the governments should be monitoring them more carefully than what they have been doing so far.

And that's the memo.

Gulf Stream weaker

Incidentally, if you still follow the speculations about the future climate, you may have noticed that the predictions of a catastrophic warming have once again been replaced by predictions of catastrophic freezing, at least for Europe. Well, because of some data indicating that the Gulf Stream may have weakened. Or maybe not. It is not hard to see that if the climate scientists (?) change "2/e" of their basic predictions every 6 months, only "exp(-100)" of their predictions for the year 2055 will survive. And that's a pretty small number - something like 10^{-40}. ;-)

Witten and Langlands

Edward Witten was speaking about the Langlands duality. The huge lecture hall "Science Center D" was completely full. Full of mathematicians and theoretical physicists. And probably many others.

It may be fair to say that Edward Witten is probably not only the holy father of theoretical high energy physics - using the term invented by Friedwardt Winterberg - but quite possibly also the most respected mathematician in the world as of 2005. This fact makes such a talk a special event; but that's not the only reason.

Of course, I apologize to all who feel that I am not fair if I put their name below Witten's name in the list of mathematicians. If you have any doubts that Edward Witten, a leading figure of string theory, has figured out important insights that have been experimentally verified, open the "fast comments" and see examples from a reader whose name happens to be Peter Woit.

The talk was addressed both to the mathematical as well as physical audiences. Recently I discussed the Langlands duality a bit and included a link to a written version of Witten's talk in Stony Brook that was similar to the talk today which is why I decided not to describe the talk in detail right now.

Update:

On Friday, Edward Witten gave another talk in "Science Center C" about various issues related to many holomorphic properties of the Bogomolnyi equations in Yang-Mills theory (which included correlators of 't Hooft loops) and about topological twists of the N=4 Yang-Mills theory.

There are three types of topological twists of this maximally supersymmetric Yang-Mills theory. Some of the postmodern "physics critics" like to admire topological field theories but they often say that they have no connections with string theory. Witten's talk has shown many things - and one of them is the fact that these "lit crits" have not only an insufficient understanding of string theory but also an outdated idea about topological field theory. In fact, the only way how you may easily remember what are the three topological twists of the N=4 Yang-Mills theory is to realize that they can be constructed as descriptions of D3-branes on supersymmetric (calibrated) 4-cycles of manifolds of three types of special holonomy:

• spin(7) - special holonomy - spin bundles are relevant
  
• G2 - Omega2+ is relevant
  
• SU(4) - Calabi-Yau four-folds

Each kind of manifold comes with its natural calibration, preserved supersymmetry, and be sure that you can always see that the theories "know" that they come from string theory and you may always find the total of 10 dimensions if you count it properly. In the last case that is relevant for the Langlands duality, you find a CP1-worth of theories. The previous two twists are analogous to the Donaldson theory.

String theory is not only the only natural organizational scheme for quantum gravity and for the explanation of the origin of fields in particle physics and relations between gauge theories, gravitational theories, and other types of physics; it is also the natural framework that gives you this portion of mathematics connected with topological field theories. Those who deny that string theory has become necessary as unifying framework for a full understanding of physics of gauge theories, gravity, topologically twisted field theories, and their relationships are analogous to those who deny that there are reasons to believe the evolutionary framework in biology.

There have been many interesting things in the talk but a more accurate report would require me to use some formulae and maybe pictures and it just seems too difficult at this moment. Neither of these things can stop Jacques Distler whose nice description I recommend you all of those who followed the abstract above.

Techcentralstation on Susskind's book

David G. has kindly pointed out an article on my favorite, libertarian, pro-business, anti-global-warming-madness server Techcentralstation.com (TCS) about string theory in general and the anthropic principle in particular:

• TCS on Susskind

Lenny's book about the stringy landscape and Intelligent Design will be released in one or two weeks, and I am sure that he realizes that it will be a highly controversial book. In fact, it is my understanding that the controversy is Lenny's main point. As you can see, the public controversy already started before the book was released.

Kenneth Silber - who has already described Brian Greene's "The Fabric of the Cosmos" at TCS - begins with a nice story how Murray Gell-Mann replied with a laughter when he first heard that particles were "elastic strings, like a rubber band" from Lenny. David Gross has had rather similar comments about the relative importance of the early papers on the subject. Silber says a couple of words about string theory and M-theory but he spends most of his time with the anthropic principle.

Well, Silber obviously has a pretty similar approach to these basic questions as I do. For example, a typical sentence about Lenny's book is

• A reader may come away from the book thinking that if string theory (as elaborated by Susskind) is wrong, the evidence points to fine-tuning by a supernatural agent. Not really.

That's spot on. Note that the term "supernatural agent" is used for what our anthropic colleagues would otherwise call "eternal inflation" or anything else. It's because their physical role is almost isomorphic: they are meant to give you the unlikely events that are necessary for intelligent life.

No one among us has read Lenny's book, but almost everyone knows what will be in between the covers because we know Lenny and we have seen the cover. The reader will be given a lot of evidence that our Universe is fine-tuned - which is morally the same thing as being intelligently designed - except that Lenny is gonna argue that his favorite solution to the apparent fine-tuning based on the anthropic principle is the "opposite" of the Intelligent Design.

It may be the opposite in the sense that Lenny's God is cold and does not like the people while Jesus Christ and His family literally loves them - but if you try to look at any measurable difference between the two origins of the Intelligent Design and fine-tuning - namely God vs. the anthropic principle - you will find virtually no difference. They share the basic idea that we may afford to believe in extremely unlikely events that do not need a deeper explanation. By these events, I either mean the events described in Genesis or its competitors, or the events of eternal inflation that intelligently choose the right rules of low-energy particle physics that admits life.

I, for one, don't see much difference between these two approaches. Kenneth Silber also assures all of us that if the anthropic principle is the way how the physicists will describe reality, the scientificially-educated public may choose to believe the postmodern "physics critics" instead. I mean the "physics critics" who are not even wrong because they fully follow the example of postmodern "literary critics" - one of these physics critics is mentioned by Silber and you know who he is.

You know, intelligent people outside high-energy physics such as Kenneth Silber may believe us that we are more experienced and better equipped to calculate the properties of physical interactions above 1 TeV of energy. But no one will convince them that they should change their opinion on whether or not we should adopt supernatural principles if things look fine-tuned to us. Of course that the opinion of the people like Silber about these issues are as valuable as the opinion of the physicists. These are questions about the basic attitude towards religion. And physics has no convincing evidence that a dramatic change of the religious opinions should occur today.

There is very little evidence of anything like Intelligent Design or many extremely unlikely events are needed for our Universe to work. Whenever we repeatedly observe something that looks extremely unlikely to us, it just means that we misunderstand something about the natural laws and we should try to do better - instead of inventing philosophical frameworks that imply that we can afford the world to look unlikely to us. This is how science always worked and it is how it will always work as long as it deserves the label "science".

And that's the memo.