Jack Sarfatti's citation

The moderators of arXiv.org may sometimes have a rather difficult life.

For example, Jack Sarfatti succeeded in submitting a paper to the gr-qc archive. More interestingly, Jack Sarfatti has inspired research in his area and a new paper by Waldyr A. Rodrigues "A Comment on Emergent Gravity" has appeared on the same gr-qc archive. Unfortunately for Jack Sarfatti, the new paper explains why every single sentence of Sarfatti's paper is a nonsense (an exercise for students).

Together with Brian Josephson and others, I just received a copy of Sarfatti's e-mail to the moderators of arxiv.org that asks them for the following:

Hi

Will I be able to post a polite response to http://arxiv.org/abs/gr-qc/0602111 in due course? Or does the archive discourage that sort of exchange? I am cognizant of not placing papers on the archive that are not of fundamental importance. Please advise.

Thank you :-)

Jack Sarfatti, PhD (physics UCal)
sarfatti@well.com

Needless to say, it is not just Jack Sarfatti who would like to fill arxiv.org with material like that. Some blogs chose the strategy to fill the arXiv with trackbacks rather than papers.

Czechia is a new donor

Paul Wolfowitz, the president of the World Bank, has just upgraded the Czech Republic from an underdeveloped country that gets assistance to a developed country that must become a donor. Is it good news or bad news for the country? ;-)

Below, you must move the stained glass to the left in such a way to match the colors of the windows both vertically as well as horizontally, so that the interior of the picture is made of single-colored squares rotated by 45 degrees. I've only finished level 1 to check that the applet works. If you finish it - assuming that it's possible - try to describe the first symbols/letters on the final screen.

A conservative martyr

Some of the very recent commentaries of the resignation of the president of Harvard University are very interesting.

Liberals can defend themselves with KGB tactics only. The Canadians explain that political correctness has always been good for everyone unless, of course, you are Larry Summers and the guys with the PC eyes come for you. In Australia they ask: and did you think that our universities were politically correct? MIT speculates that the next president will be namby pamby who "rose quietly through the ranks". They also mention that Summers has autographed many dollar bills for admiring students. I must emphasize that it was not just students. It was also for senior professors but also junior scholars like me.

Another newspaper explains that Larry Summers has become a conservative martyr. In this article, David Horowitz concludes that Summers is a liberal but he has been doing the right things. The universities have been taken over, he says, and it is about 10% - the hardline Stalinists - who got rid of Summers. The article argues that moderates as well as some liberals realize that Horowitz is essentially right. In another text, Karl Maher hypothesizes that the events at Harvard will cause the end of political correctness. Mark Sevelis compares Summers' story with that of Herb Kohl. David McClintick who wrote the article about "Harvard in Russia" takes "credit" for the resignation in the New York Times.




The previous article about the numerous responses to Summers' resignation is here.

Interaction-free measurements

I feel slightly dissatisfied with the way how the physics blogosphere described the recent media explosions about the so-called interaction-free measurements, especially because the blogosphere has made the question about the origin and originality of the ideas even more obscuring than the media. See news.google.com for the recent articles about quantum interrogation which is another name for these phenomena.



First of all, it is surprising that not a single of these media or blog articles mentioned the names of the physicists who actually invented quantum interrogation or interaction-free measurements. So who are they? Their names are

• Avshalom Elitzur and Lev Vaidman

and the discovery was made in 1991 although the paper only appeared in a proper journal in 1993. The first experiments occured eleven years ago, in 1995, with the names of Paul Kwiat as well as Anton Zeilinger on the paper. Zeilinger, who is a leading Austrian experimenter in the field of quantum teleportation and related topics, had done some very closely related experiments already in 1994. The originally low efficiency of the interaction-free measurements was improved in 1999 in a paper by Kwiat et al., including Zeilinger.

What are these discoveries all about? Let me start with...

Zeno's paradox

The ancient philosopher thought that an arrow cannot really move because you can divide its path into infinitely many pieces, and because the total length of each piece is zero, Zeno thought that their sum must also be zero, and an inconsistency of mathematics is then a trivial corollary. Zeno was apparently unaware of the fact that "0 times infinity" can give a finite result.

He had also invented other paradoxes that are not relevant for the main point of this article - for example, in his "Achilles and the turtle" paradox, he showed that he thought that the sum of an infinitely long sequence of positive numbers (such as the geometric series in his case) had to diverge. Although these Greeks started science - the Euclidean geometry may be viewed as the oldest field of physics describing relative positions of perfectly solid bodies - truth to be said, their ignorance was often breathtaking. ;-)

Quantum Zeno effect

Let us jump by several millenia into Zeno's future. Consider a two-level system in quantum mechanics. For example, take an excited atom that is ready to decay into its ground state. Normally it takes some time T but if you keep on measuring the energy of the atom very frequently, you prevent the atom from jumping onto another level. Much like Zeno thought, if you divide the time into infinitely many pieces - and you insert measurement to each point - motion becomes impossible.

Another example is a particle that is able to tunnel through a barrier. Such a thing can occur in quantum mechanics but only if you give the particle enough freedom to be invisible for a while and re-appear on the other side. If you watch the particle permanently, the tunneling can't take place. Because of the same reason, the economy can't operate well under a Big Brother who is permanently watching i.e. in socialism.

OK, we know what the quantum Zeno's effect is about.

Interaction-free measurements

The improvement from the 1990s is that you may also want to look at a different place from the location of the particle, and you can still learn something about this location. The classic example is a light-sensitive bomb. Can you see (optically) whether the bomb is in the box while avoiding detonation? The answer is Yes, Elitzur and Vaidman argued. Click at the word "bomb" in this paragraph (don't be afraid, it will probably not explode) and you will learn how can you sometimes become sure that a bomb is able to explode without actually exploding it.

Sean Carroll has recently become famous for replacing an exploding bomb by a barking dog and the igniting photon by salami.

See this paper for a description how the Elitzur+Vaidman paper was written and why is the adjective "interaction-free" misleading (and dependent upon your interpretation of quantum mechanics) for these experiments. Lev Vaidman is by the way also one of the key players behind quantum teleportation. In 1999, the methods were improved by dividing the interference to many pieces, i.e. by using the quantum Zeno's effect mentioned above. See Kwiat's page for details.

At any rate, the ideas of Elitzur and Vaidman are primary, the infinitesimal "quantum Zeno" improvements in 1999 are an interesting addition to the original discovery, the experiments are rather straightforward, and the recent connections with quantum computing probably have more marketing than physics in it, especially because the concepts of "counterfactual computation" have also been known at least for 5 years.

A Christian graduate student could also use the same mechanism to experimentally reconstruct the events in which God initiated Jesus Christ without ever touching Mary. ;-)

If someone is convinced that the "counterfactual computation" can circumvent some problems in quantum computing and either reduce the error rate or decoherence, the most obvious way to use this insight is to build a working & large enough quantum computer. That would be really cool.

Similarity with Afshar

Incidentally, there is some remote similarity of these experiments with Afshar's experiment. Afshar also uses "negative information from scattering" because if you remember, he places the grid at the interference minima. His photons then interact with the grid much less than they would interact if the grid were placed at generic places (this is the counterpart of the bomb not exploding most of the time - or the dog not barking). Afshar then incorrectly interprets this setup as a 100% measurement of the wave properties by each photon, and he continues by saying that he can also measure 100% of the "which way" information - which verbally contradicts the complementarity principle.

I have argued that most photons in his setup cannot be argued to have measured the wave properties of light because they failed to interact and paint any interference pattern.

Keith Baker: TRT at ATLAS

I just returned from a colloquium about the LHC. Keith Baker from Hampton seems to be a very good speaker and he gave a convincing and inspiring talk. A bigger one half of the talk was about experimental high-energy physics - with some elementary introduction about the energy scales of the Universe - and a smaller one half was about the black physicists and related policy issues. The speaker was an African American himself.

The LHC will be completed in 2007. There are two major detectors: the CMS on the French side and ATLAS on the Swiss side. Baker and his collaborators work for ATLAS, much like some people from Harvard and many other places.

While Harvard is focusing on the muons, among other things, Hampton University's main interest is TRT which stands for transition radiation tracking. (In fact, TRT seems to be the "most American" segment of the LHC.) When charged particles move from one environment to another, they emit transition radiation and its detection is a useful tool to identify the particles and figure out other things, too. Baker described how well can they distinguish electrons from pions or how they attack the question of the angular distribution and others.

He also showed some maps and graphs of the grid. Hampton has 5 computers in it which is less than the BU+Harvard group but these five computers are run primarily by students and they are important for other reasons discussed below.

His main motivation was to confirm or falsify the Randall-Sundrum models of a warped extra dimension - and they can essentially complete this job within a year or so after the LHC starts, assuming a certain upper bound for the "amount of fine-tuning" in the RS theories. If you draw the parameter space of these models, a part of it is already excluded by experiments that have been done. Then there is a "fuzzy" boundary on the right side of the diagram imposed by the assumption of the absence of fine-tuning, and the precise nature and justification of this boundary was the topic of some debates.

What you actually want to detect in these models are the narrow resonances describing the excited warped KK modes of the graviton. A quark-antiquark pair annihilates into the excited graviton which subsequently decays into a lepton-antilepton pair. The main background is, of course, the same process with gluon as the intermediate state, and some extra work is needed to distinguish them from each other.

One question was about the coupling constant of the SM particles to this excited graviton mode, and I am not sure whether the answer was quite correct. I don't think that the rest mass influences the coupling of very high-energy leptons to the excited gravitons. Our phenomenology students quite certainly know the right answer but they did not intervene in this discussion.

Black colleges

Another important part of the colloquium was devoted to the role of the historically black colleges and universities (HBCUs) in particle physics. There are roughly 100 colleges, mostly in the Southeast of the U.S., that were created to educate the former slaves after slavery was abolished. (The oldest HBCU was founded in 1837, however.) Hampton University is the only one that has a PhD program and Baker's talk has shown that they are doing quite a serious and meaningful stuff. At Hampton, an unusually large portion of the work is done by students.

There were some funny moments - for example, when he was showing how good different teams working for ATLAS are, Hampton University was almost the best one in one aspect except that some Russians turned out to be ahead. Still good.

Despite being open-minded about the best arrangement, Baker has made a pretty good case for the HBCUs - someone may call it a case for "segregation". Unlike most of the far left-wing whackos, he seems to appreciate many aspects of reality. He discussed what thoughts the black students actually have when they decide where to go. They want a place with many potential partners (I mean girls and boys), and as far as physics is concerned, those who can make it often prefer the "majority" universities.

Baker says that the average students work on whatever they are asked to work on as long as they are paid. The best students want to work on cutting-edge problems, and if Hampton University is not able to show them that they will have a better environment than their colleagues at Harvard or elsewhere, then Hampton will rightfully lose these students, he said.

Also, and this counts as an advantage for HBCUs, the good students want to feel that they are as special and excellent as the good majority students do, and this goal may be easier to achieve with this "segregation". Some of Baker's arguments about educating the black elite were similar to those of La Griffe du Lion who praised the basic principles of the Meyerhoff scholarships which were very successful at least back in 2000.

Another simple reason why HBCUs are important is that a rather large majority of degrees awarded to the blacks comes from these schools.

MetroRail anagrams, FOX screenshots, and conservative idiots

Ethan has the Houston light rail train station names in anagram here. Boing Boing has dozens more cities treated similarly.

These FOX screenshots capture the majesty of their propaganda. The real outrage is that this is the most watched cable television "news" in the United States; 2-to-1 over CNN.

And the Top Ten Conservative Idiots once more features the President of the United States with this lede:

It's hard to believe that just one week after the vice president of the United States shot a man in the face, an even bigger story would come along. But here it is: last week the Bush administration approved the sale of the operations of twenty-one major American ports to Dubai Ports World, a company owned by the government of the United Arab Emirates.

He's number one. He's number one...

Curt Gowdy, Don Knotts, and Darren McGavin

They say they come in threes; these television icons -- to me -- all passed away this past week.

I remember Curt Gowdy from the Game of the Week broadcasts in the '60s. This was the only baseball you could find to watch at the time. About the same time I was becoming a Astros fan and listening to Gene Elston (congratulations to him on receiving the Ford Frick award this week) and Loel Passe ("breezed 'im one mo' time") on the radio, I was watching Gowdy and Tony Kubek on the tube. He also did the World Series as well as some of the first Super Bowl telecasts. The ones I clearly recall were III -- which was the seminal moment for Joe Willie Namath and the AFL -- and V, which was the first one the Dallas Cowboys played in (they lost, on a last-second field goal to the Colts, which nearly made me kick in the screen). Gowdy was just as famous for being a Red Sox broadcaster and for The American Sportsman, but to me he'll always be baseball on Saturday afternoons.

Speaking of firsts, the first thing my family ever saw on our new console color television was Don Knotts and "The Incredible Mr. Limpet". I believe it must have been 1965, since the movie premiered in '64.

And if you watch the Sci-Fi Channel you can still catch episodes of Kolchak: The Night Stalker, which made McGavin famous to me long before A Christmas Story, the "major award", and "you'll shoot your eye out". Those old Night Stalkers look awfully cheesy now, but at the time I was just short of terrified once a week by them.

RIP to three good men.

Smart frog

What a bright animal.

Moneyshot Quotes: Conservatives ready to cut and run from Iraq, port storm rages, and Jeff Bagwell arrives in Florida

Rush Limbaugh says we can't win (.mp3), Bill O'Reilly says we need to "hand everything over to the Iraqis as fast as humanly possible", and Wiiliam F. Buckley says we must "acknowledge defeat".

This is what Howard Dean was saying months ago, wasn't it? Yet he was vilified.

The Port Storm isn't subsiding. Bush digs in his heels, and the Republicans prepare to throw him, and the deal with Dubai, over the side. Since we're assembling Moneyshot Quotes, here's two more:

Thomas Kean, head of the 9/11 Commission:

"It shouldn't have happened, it never should have happened," Kean said in a telephone interview with The Associated Press.

The quicker the Bush administration can get out of the deal, the better, he said. "There's no question that two of the 9/11 hijackers came from there and money was laundered through there," Kean said.

President Bush, making sense for once:

"This deal wouldn't go forward if we were concerned about the security for the United States of America."

And finally, unrelated to any of the preceding, Jeff Bagwell had this to say about his disagreement with Astros management over whether he can still play:

"I understand the business side of baseball. If I cannot play baseball this year, and I am physically unable to play with the Houston Astros, trust me, I want them to collect as much insurance as possible. I'll write the letter. That's not an issue for me. But I just want the chance to see if I can play."

My one editorial comment for the day: Bagwell is the best player the Houston Astros have ever had, and I sincerely hope Drayton McLane won't piss in his brain again.

Salman Awan: The truth is...

The truth is, The Prophet of Islam can neither be symbolized/drawn nor can be characterized in any way and anytime.

First of all I would like to pay my gratitude to Mr. Luboš Motl for giving me an opportunity to express my point of view on Danish Cartoon illustrations. Secondly, English is not my first language, however, I will try to communicate the intended message at the top of my abilities. Thirdly, most of you won't agree with what belief we Muslims and majority of the world share, but I am happy that I am into the act of Jihad through Pen.

Well, I am studying Business here in London and I am a Muslim by religion.

Firstly, I would to clear some misconceptions about Islam. Islam means "to make peace" and it struggles to maintain peace. We are no way terrorists, but all over the world we are looked upon as terrorists only because of few individuals who misunderstood the true meaning of Islam and were used by some economies for political reasons and benefits. After the 7th July, 2005 incident I have been stopped and searched 23 times at various London Underground Stations under a section, which says that I might be a terrorist. Well, that's another issue but the issue I will discuss here is concerning the height of disrespect our Prophet (PBUH) is treated with.

There is a lot happening at present in Muslim countries and wherever Muslims live. Yeah, its all emanated from Danish Cartoon Illustrations (DCI), moreover, these DCI are compelling Muslims to be defensive. Condoning or punishing such acts is a personal opinion shaped by religion, culture, values and heritage.

Prophet Muhammad (PBUH) was the last of all messengers and Islam was completed during his life. For us, Muslims, he is the best of all human beings and we try to follow his footsteps in every walk of life to get the best of the both worlds. Concisely, he is a model of excellence, and our love for him is unlimited.

The Prophet's Distinctive Characteristics as a Reformer

1. The most Successful of Prophets
2. Universality of the Message
3. Unity of Human Race
4. Development of entire Human Race
5. Greatness in all Directions
6. Not a Product of Environment
7. Universal Peace

The Prophet's Sublime Morals

1. The Prophet, an Exemplar
2. No Work was too Low for him
3. Simplicity
4. Food
5. Dress
6. No Attraction for Comforts
7. Cleanliness
8. Love for Friends
9. Generous to Enemies
10. Equal Justice for all
11. Humility
12. Sympathy for the Poor and the Distressed
13. Hospitality
14. Gentleness
15. Faithfulness
16. Forgiveness
17. Modesty
18. Affection
19. Respect for Others
20. Courage
21. Steadfastness

He possessed all the qualities we can think of and the qualities beyond our imagination. All these attributes make us fall in love with him. The DCI aimed to depict him as violent and terrorist minded, moreover, it's an attack on his attributes and not only that every Muslim is deeply offended and insulted our religion Islam is also disgraced and disrespected. I will not forgive such callous, disdainful, condescending disregard of things dear to me, things that I love.

No one has ever dared to draw his sketch except DCI, it's because of the respect we all hold for other religions. As CNN refused to post the DCI:

"CNN has chosen to not show the cartoons out of respect for Islam."

(This comment by CNN is an act of respect)

He was so perfect that we cannot bear anyone manifesting him as a terrorist or any other character as depicted by DCI. We treat each other with respect, I have respect for your values and religion it doesn't means that you can abuse my Prophet or Allah. Cartoons are no way means of depicting such personalities. The truth is, The Prophet of Islam can neither be symbolized/drawn nor can be characterized in any way and anytime.

It's a grave mistake by the Danish Prime Minister to oversimplify it into an issue of freedom of speech and religious sensitivities; it would miss the point completely. The Danish editors cannot claim that they were only exercising freedom of expression because hiding behind that guise would misrepresent what they did, and what they did was deliberately incite. That defeats the very purpose of a freedom of expression.

What should we do? We will be intolerant of such actions. We will not pretend that you have the right to insult our religion. But, we will be intolerant without being violent. We will use this forum of speech, and expression and non-violent action, to make ourselves heard. This is not on. This will never be on. We will fight, but our fight is not violent, at least not yet. Freedom of expression is not a vice. It is a virtue. Let us not forget that. Let us not forget that it is open to us too. That we can tell them it is wrong, and we can continue telling them, until they listen to us. But just because they don't listen to us right now, does not mean we burn and we torch, and we kill. Our fight is better than that, our fight is smarter than that. It is a longer, more difficult fight. But it is the right fight. And that is what matters. That is what Muslims are supposed to be about.

Also, I will make it crystal clear that who the fight is against. It is not against a civilization. It is not against non-Muslims as a whole. It is not against American governments as a matter of default. Our fight is against, those who believe our religion is not worth being respected. We need to earn our respect. We earn it, by being patient, by showing all the good that our religion stands for. We earn it by respecting them, and by respecting theirs. That is what we do.

So far there have been some deadly protests and I stand against them.

Salman Awan
awansalman at msn.com

Neumannová, Swedes, and taxes

I have finally received my 2005 tax refunds, both from the state level as well from the Feds. Filing as a resident has trivialized this portion of bureaucracy and I only spend about 5 hours a year or so with the forms for IRS and DOR. It used to be completely out of control when the various forms reflecting the international treaties had to be filled out - several weeks of the process of figuring out what to fill out and what to write in the forms. And I still didn't know the answer to some very basic questions like Whather I should pay any taxes or not. Despite the simplification, yes, I still think that taxes should ideally be eliminated or at least replaced by some concise flat or fair tax system.

Kateřina Neumannová got a virosis two days ago so she had to decide whether she would compete in 30 km cross country skiing - free style (skating) - at the end of her last olympic games. The final decision was yes and of course, she has won the gold medal, improving the Czech medal budget somewhat. One of her previous gold medals was right after she gave birth to her daughter Lucie. Is not she amazing?

The Czech ice-hockey players face Sweden in the semifinals at 10:30 am EST today. The Swedes want to revenge for their lost semifinals with the Czechs in the 2001 semifinals, for their unsuccessful attempt to revenge in the 2004 World Cup in Sweden in which the Swedes lost 6:1 in front of their own fans, and for their futile 2005 attempt to revenge for their failed revenges in Vienna. Well, quite a lot of stuff to revenge for. ;-) Important background: the Swedes stole a lot of books, gold, bronze statues, fountains, and other good stuff from Prague in 1648 and it seems that their conscience has not yet been cleared. :-) Unfortunately, the Swedes are going to win today 7:3. Note that I don't like the Bayesian inference so I prefer to tell you the result instead of some meaningless figures encoding the "probabilities".

However, on Saturday, the Czech team will easily beat Russia 3:0 (1:0 - 1:0 - 1:0), humiliate lonely oyster's predictions, and grab at least the bronze medals. Sweden will win the gold medals by a 3:2 victory over Finland on Sunday, leaving the Finns with the silver medals.

Values in physics

Physics is a science and the experiment is the ultimate judge of the validity of the physical theories. At the same moment, the idea that the search for the truth in physics is just a sequence of mechanical tests of theories against well-defined experimental data that reveal the truth step by step is a narrow-minded illusion.

The ideas in physics are often much more far-reaching. Their importance often exceeds the impact of philosophical or religious dogmas. In fact, some ideas in physics are so far-reaching that they determine not only the answers but the character of the very questions that are going to be asked for many decades or centuries after the original ideas or principles are revealed. Sometimes we talk about "beauty" in physics but different people often have different features of the theories in mind.

I would prefer to be slightly more specific - as specific as a philosophical essay allows one to be. Some of the main values that may determine the depth of principles and theories in physics may be described as follows:

• uniqueness & rigidity
• inevitability
• self-consistency and mutual causal relations between different statements
• ability to avoid inconsistencies, especially if consistency is not guaranteed from the beginning; equivalently: the existence of miraculous cancellations of inconsistencies
• limited number of independent assumptions
• ability to be relevant in a large number of situations
• power to organize previous systems of ideas and reveal new relations between them
• multiplicity of descriptions of the same structure that are mathematically equivalent
• the maximal possible yet finite amount of complexity of these theories that still makes them compatible with fundamental principles

While I find it obvious that all of these features are important and contribute to the feeling that an idea or a whole framework is on the right track, each of these characteristics has its foes. In fact, there are many people who will tell you that each of these properties is in fact a disadvantage.




Many people will tell you that their proposed theory is good because it is not unique. They will try to convince you that their theory is good exactly because one can deform it in a huge number of ways. One can add anything to these theories. Well, I beg to differ. Valuable theories are always very special animals. Given some assumptions or principles - that must themselves be deep and we will mention some examples later in the text - a valuable theory must be unique or nearly unique. It must look like a golden needle in a haystack. And the criteria that determine which particle is a golden needle must be universal and robust, too.

The mathematical ideas of calculus invented by Newton and Leibniz were inevitable and in some sense unique. The actions defining laws of classical mechanics are not too numerous. The rules of field theory become even more constrained once we assume a beautiful principle such as the Lorentz symmetry. The principles of quantum mechanics are the unique extension of the naive classical deterministic laws that is compatible with the basic rules of logic. The Lagrangians for renormalizable field theories are extremely special because generic Lagrangians lead to a breakdown of the theories at higher energies.

Yang-Mills interactions are inevitable because they are the only known way how the interactions may grow weaker at shorter distances. Their structure requires us to consider theories with local gauge symmetries which are themselves "beautiful" and constrain the matter spectrum and the character of the interactions.

Let me now assume that the reader understands that the theories must be very special and predict a maximal number of consequences from a minimal number of independent assumptions. We don't necessarily need to minimize the number of assumptions and independent concepts as much as we can. Instead, we may work with a larger number of assumptions and objects, but we must always appreciate when some of the assumptions imply others - so that the set of assumptions does not feel disconnected.

It is not "bad circular reasoning" but rather "good rigidity"

Much like all other positive values in physics, connectedness of the ideas has its enemies. Some people will argue that a theory is not good enough because it is based on circular reasoning. This is an argument that some philosophers are ready to use against intellectual structures that are as essential as the theory of relativity - a system of ideas that is more impressive than all ideas ever invented by all philosophers combined.

Is it bad that different statements in relativity follow from each other? Not at all. Every theory must have some assumptions. And if the assumptions tend to imply each other - while still being able to underlie non-trivial and numerous predictions that may even confirm the experiments - we should definitely be more happy, not less happy.

Quantum field theories have the feeling of "relative uniqueness" and string theory offers an "absolute uniqueness" - the first theory the humans ever knew that is capable to do so. This statement does not mean that string theory only has one solution. Of course, it can have many "classical" solutions, asymptotic conditions, and huge Hilbert spaces built upon them. But the dynamical laws that determine which of these spacetimes and states exist and how they evolve are completely unique.

Whenever I talk with someone outside the mainstream high-energy physics, it becomes very clear that many people at the suburbs of the field have absolutely no understanding for these basic principles.

Simplicity and beauty

Another notion that very many people seem to misunderstand is simplicity. Are the laws of Nature simple? Well, it depends how you define the word "simple". We may start with the definition that the laws of Nature are accessible to people with a minimum required IQ, education, or effort. Are the laws of physics simple in this sense? No way. Indeed, as our understanding of Nature deepens, one must - fortunately or unfortunately - learn ever more profound concepts that become increasingly inaccessible to ordinary people and sometimes even to the experts.

Simplicity vs. brevity

Let us try another definition of simplicity. Simplicity may also be defined as the number of T-shirts or pages that we need in order to print all essential rules that will be comprehensible to an intelligent reader. Is Nature simple in this sense? Well, this definition is closer to the truth than the previous one. Indeed, many defining formulae of physics are very short and efficient.

But some of them may be rather long - but equally or more beautiful or fundamental. For example, the full Lagrangian of 11-dimensional supergravity is a rather complicated monster but it does not make it any less beautiful. What is important is that the individual terms in the Lagrangian are not independent from each other. In fact, the whole structure of the two-derivative Lagrangian is uniquely determined by the requirement of supersymmetry.

One of the comments in the list above was a variation of Gell-Mann's totalitarian principle: everything that is not forbidden is compulsory. We should always consider the most general theory that respects the same symmetries and other principles and is equally consistent as the first idea in the class of theories that we have encountered, discovered, or invented. We should never focus on a special, randomly chosen theory that does not differ from many others by the validity of any fundamental principle. We should never try to fool ourselves and others by pretending that such a randomly chosen representative is more important than other random elements of the same set. And we should never study theories with infinitely many parameters, all of which are strongly relevant for the questions that the theory is supposed to answer.

While Gell-Mann would probably think about our duty to add all couplings that respect the rules of the game, it is true that we must also accept all discrete choices for our theories that respect the same principles. Some of these theories may look rather complicated - for example, some people may think that the "E8 x E8" group of a ten-dimensional heterotic string background is too large - but similar theories are important nevertheless because of much more crucial reasons that a naive notion of simplicity.

Symmetries and other valuable principles

When I said "supersymmetry", it is indeed a good opportunity to mention what are the important principles that distinguish which object is the golden needle in a haystack of ideas. Some of the previous "valuable ideas" could be added to this list if we interpret them slightly differently. But we must also include more concrete principles that seem to be absolutely true in the real world, according to everything we know:

• Basic postulates of quantum mechanics - observables are linear operators on a Hilbert space and time evolution is given by another linear operator
• The evolution operators must be unitary to preserve the total probability since the probabilities are computed from squared complex amplitudes
• Dynamics must be local, at least approximately; we discussed locality here; locality is related to causality, another important principle
• Important symmetries should be respected

Symmetries of course play an important role in the scheme of things. Which symmetries do we mean? First of all, it turned out that the discrete symmetries are not terribly constraining and Nature does not care about them too much. People used to think that there was no difference between the left hand and the right hand; between particles and antiparticles. People used to think that C, P, T, and CP were symmetries of Nature.

Today we know better. These symmetries are broken and only the CPT symmetry seems to be the ultimate rule that survived. And it is only true because it can be interpreted as a particular element of a properly extended continuous symmetry, namely the Lorentz symmetry.

The Lorentz symmetry

Well, the Lorentz symmetry and its affine extension, the Poincaré symmetry, is an extremely important principle. This symmetry is a fundamental pillar of special relativity and it includes, via Noether's theorem, the conservation of energy, momentum, angular momentum, and the uniform motion of the center of mass. This symmetry relates many physical phenomena that were considered to be independent: magnetism is an inevitable supplement of electricity once the Lorentz symmetry is assumed. The existence of conserved energy follows from the existence of conserved momentum and vice versa. Moreover, the mass and the energy have to be equivalent and convertible to each other. Many other effects and notions that were independent are unified.

General relativity as a generalization of special relativity

Some people are extremely confused about the nature of special relativity and they will tell you that the discovery of general relativity has revoked the constraints imposed by special relativity. But that's another extremely deep misunderstanding of physics. General relativity is called general relativity because it generalizes special relativity; it does not kill it. One of the fundamental pillars of general relativity is the equivalence principle that states that in locally inertial frames, the laws of special relativity must be satisfied by all local phenomena.

The global Poincaré symmetry of special relativity is extended - or generalized - to the local diffeomorphism symmetry of general relativity. All observers are equally good for formulating the laws, not only the inertial observers. For a simple topology of spacetime, the symmetry of special relativity is a very small subgroup of the symmetry group of general relativity. For other topologies such an embedding can be more subtle but it is important to see that the laws of physics are still constrained by equally strong rules like those in special relativity. The idea that the constraints of special relativity may be forgotten after the papers published in 1915 is a symptom of a breathtaking ignorance.

Some of these people will tell you that the Lorentz symmetry is broken by particular backgrounds or solutions in general relativity and therefore it is no longer important. Well, Lorentz symmetry is spontaneously broken by virtually all configurations you can imagine - both in general relativity as well as special relativity - but in both cases, it is a spontaneous symmetry breaking. What is important is that the underlying laws respect the symmetry: the diffeomorphism and the local Lorentz symmetry of physics. A correct theory based on general relativity must admit a Minkowski (or de Sitter or anti de Sitter, which are equally constraining) solution.

Local vs. global symmetries

The diffeomorphism group is a local symmetry and at the quantum level, all states must be invariant (singlets) under all these local symmetries, much like in the Yang-Mills case. This is why the representation theory of the local, infinite-dimensional gauge groups is irrelevant for physics. On the other hand, states do not have to be invariant under global symmetries such as the Lorentz symmetry, which is why the representation theory of the global symmetries is physically important.

Special relativity is embedded in general relativity in such a way that its global symmetries become generalized examples of diffeomorphisms - that are however "large" in the sense that they are not generated by normalizable modes and therefore are not required to keep the physical states invariant. The generators of time translations and similar geometric operations map the points in the asymptotic regions of the spacetime to other points, and this property is enough to revoke the requirement that the physical states must be invariant under such operations. This is why non-zero (ADM) energy and momentum is possible even in the context of general relativity, even at the quantum level.

Even though the details how the requirement of the Lorentz symmetry - and analogously unitarity - is realized in a given formalism may be subtle, it is absolutely essential to realize that these principles must still hold, and if they are replaced by something else, this "something else" must be at least equally constraining as the original symmetries were in the original theories. Sorry to say but those who say that one can simply forget about unitarity or the Lorentz symmetry altogether are simply idiots.

Cheapness of field redefinitions

Some people are impressed, for scientifically unjustifiable reasons, by random field redefinitions and random functions into which various observables are substituted. Imagine that you are an economist and you invent that instead of the interest rate "X", you should study "Gamma(-1/X)". Because you know the Gamma function, you will say that it is an extremely advanced idea in economics to use "Gamma(-1/x)" instead of "X".

Of course, this example is one of the most pathetic example of a meaningless mathematical masturbation that you can invent. Nevertheless, some people apparently like to play with useless and unjustifiable constructions that are not unsimilar to one from the previous paragraph. Note that if you just redefine some things, you don't gain new physics, new ideas, or new principles. What can happen is that it becomes easier to solve a certain problem and/or invent a new idea or a principle. But one can always translate the insights to the previous variables. At the end, one should be using the variables in which the important features of the physical system are most transparent.

If a system of equations looks "simple" in a random unnatural choice of variables - in which the important principles don't look transparent - then such a "simplicity" is a disadvantage, not an advantage.

Inventing a convoluted system of formulae just because someone likes to obscure things is not tolerable in physics. A random new choice of variables is only justified if it allows one to find some important, unique, universally relevant new solutions, or if it is helpful to illuminate the validity of some key principles - such as unitarity, finiteness, Lorentz symmetry, or some kind of duality. Changes of variables that can't do anything like that have no room in physics. One can never assume that a random change of variables will lead to an interesting new physical idea without having any evidence, and one should never believe the people who are building their perceived "depth" on obscuring things by introducing physically unjustifiable changes of variables.

Dualities and multiplicities of equivalent descriptions

Finally, I want to mention dualities as another feature of theories that are likely to be deep and on the right track. Dualities and multiple descriptions of the same physics certainly did not start with string theory.

Classical physics could have been described by the Lagrangians as well as Hamiltonians. One could have used different coordinates and trivially show that the laws were equivalent. More strikingly, quantum mechanics could have been formulated in the Schrödinger picture, the Heisenberg picture, the Dirac mixed picture, or in terms of the Feynman path integral. The wavefunctions could be represented by functions of coordinates, functions of momenta, or discrete columns of complex numbers that encode the amplitudes of various energy eigenstates. All these approaches turned out to be equivalent although it was not obvious from the beginning.

Is it a bad thing for a theory to have many equivalent languages or formalisms? No way. It was one of the extremely important hints that quantum mechanics was a deep structure. Today, the mathematical facts behind these equivalences look trivial to most of us. But we have new, more impressive equivalences in string theory whose validity seems obviously true but whose "proof as clear as skies" is not yet accessible. In the future, people will most likely find new insights that will make the dualities and equivalences between different descriptions of string/M-theory more transparent. But the very fact that there exists some equivalence that is not immediately obvious suggests that there is something really intriguing to study.

The previous sentence contains the word "immediately". Indeed, if the equivalence of two pictures is immediately obvious, we don't want to count the multiplicity of descriptions as an argument for anything or against anything. The fact that we can use different letters or metric conventions or other conventions (including field redefinitions discussed above) does not mean that we necessarily deal with a deep set of ideas. In fact, it is always possible to formulate any kinds of ideas in different languages. We can only conjecture that we are facing an important idea if the equivalence between the different descriptions that superficially looked inequivalent takes some time and reasoning to be revealed.

Much like in the cases of all other important values in physics, many people are so profoundly confused that they count multiplicity of equivalent - but not manifestly equivalent - descriptions as a disadvantage. On the contrary, these people often prefer narrow-minded formalisms that can only be formulated in one way. They like if their proposed theories can't be connected with other ideas. They like if their colleagues have only mastered one small segment of mathematics. They like if their theories can only be written in the Hamiltonian form but not the path integral form. They don't mind if different approaches that normally lead to the same results give contradictory results in their case.

I beg to differ. Theories should be connected with all formalisms we have used to describe all important classes of phenomena in the past. All methods we have learned in the past should have a correct and sharp generalization that allows us to treat the newly proposed theory. The existence of several non-equivalent approaches is always an advantage. It is a practical advantage when we try to solve or understand the theory: much like other symmetries, dualities can help us to solve particular problems. At the same moment, it is a hint that we are uncovering a huge empire in the world of ideas, not just a fiber in haystack.

We should always remember which features of the ideas and theories that we think about suggest that something important is being uncovered, and we should always point out if someone tries to replace deep and viable principles by shallow, random and unjustifiable dogmas.

And that's the memo.

It's Harvard's loss

As you know, it is not unusual that after summers, there are falls.

The world's media seem to agree. Look at the articles about Summers and Harvard offered by news.google.com.

• Summersville, a blog dedicated to Summers
• A defenestration at Harvard The Summers also sets (The Economist about jihad against Summers and freedom)
• Another Academic Casualty
• Feminist Victory
• At Harvard, many students lament Summers' departure
• Alan Dershowitz: Lawrence Summers's Dishonest Opposition
• Students Hail Harvard President, showing a shift in campus politics
• The victory of Lilliputan adversaries of the president of ideas will have destructive ramifications
• Campus Political Correctness Revealed By Resignation & a donor lost
• Summers' end
• Loss Of Summers’ Strong Leadership A Shame
• Summers learned Harvard doesn’t want change
• Harvard Loses in Summers Protest Saga
• It's Harvard's loss
• A Legacy of Searching for the Truth
• University at a Crossroads
• Summers Was Always Supportive of Law School
• Leaders Who Listen
• Losing Money on Larry
• Alumni See Summers As Strong Leader, Not Firebrand
• HARVARD ISN'T WASHINGTON
• Summers: 'I've Made My Share of Mistakes (but he got the most important vote of confidence, from Elisa New, and he was the first president under whom Harvard always defeated Harvard for dummies, also known as Yale University)
• Past Presidential Searches Give Clues; Chiefs of Other Schools and ...
• Faculty Will Take ‘Time To Settle’ (the faculty meeting on 2/28 is cancelled)
• Summers over
• Summers Resignation Indicative of Intolerance
• Harvard's Loss (New York Sun) - Summers only resigned after credible threats that the segments within FAS would blow up the Harvard stadium
• Another Academic Casuality: Harvard University Ex-President ...
• Summers‘ Resignation Divides Harvard
• Summers waged final, futile battle
• Faculty’s Actions Will Harm University in Long-Run
• Harvard's beheading
• Harvard Loses in Summers Protest Movie Script
• Sticks and Summers (the sticks are feminist fantods)
  
  
  
  
  
• Summers and the Students - Summers stood for many things, especially the students
• Harvard Guessing Game to Replace Summers Brings Up Mostly Women
• RIP Harvard President Lawrence Summers
• At Harvard, Resignation Puts Big Plans on Pause (New York Times)
• Larry Summers concedes to his foes (Financial Times)
• Fed Vice Chairman Ferguson Quits, Adding to Turnover (Update5) (Ferguson was Summers' classmate)
• Just Change the Name to Hervard (Rush Limbaugh)
• Harvard: Rich, prestigious and unmanageable? (Boston Globe)

Indeed, the linkers-not-thinkers have a very easy life.

The battle is on over firing

Union says it will fight to get officer's job back

Interesting news from a virtual world via Charles Marcus - a world where the good guys may actually be bad guys and where dismissals have a rational cause.

FLINT (WJRT) - (February 06) - An officer is off the streets this noon, having been fired for his actions in a high-speed chase.

That chase led to a fiery crash and the death of Fisher. [Prof. Fischer is a physicist who proposed an anti-Summers resolution.]

Police say Officer Summers was behind the wheel of a cruiser when it slammed into Fisher's cruiser in a Boston neighborhood. The department fired Summers, saying he didn't follow proper policy.

A police captain said this morning that they had issues with Summers' overall job performance. He's the only officer to face discipline for what happened that night.

An effort is already underway within the Department to get Summers back on the job.

Here's the background on the case.

Back in 2005, Freeman fled from officers after having open alcohol containers in their car. That started the high-speed chase, leading to the fatal crash.

Bentoski and Freeman reached plea deals last month with prosecutors.

Officers Fisher and Summers were part of the chase. Summers' patrol car hit Fisher's, causing the fiery crash.

As part of the lengthy investigation into Fisher's death, the department decided that Summers didn't follow proper chase policy.

Department administrators won't talk on camera. Scott, however, did give us a statement this morning. The document says the department terminated Summers based on what happened in 2005 incident and his overall job performance.

He also said this happened only after their extensive investigation.

Union leaders say they'll file a grievance against the Department and fight for Summers job.

More details here.

Ice-hockey update

In the previous article about ice-hockey, another piece of evidence that the Bayesian reasoning is flawed was offered by the second anonymous "fast commenter" who has made the following prediction:

• The Bayesian probability of [Switzerland] winning gold is definitely higher now, whereas a frequentist wouldn't be allowed to put his two cents into the debate

Indeed, I said, the frequentist approach to probability does not allow us to say much, and if it does - and if it is combined with common sense - the result will be, of course, that the probability of Switzerland getting the gold is tiny. Most likely, Switzerland would be eliminated in the quarterfinals because it used to be frequently eliminated. ;-)

Needless to say, the Bayesian inference has been proved wrong once again and I was right - despite several fascinating previous matches, Switzerland has lost to Sweden 2:6. Canada won't defend its 2002 olympic gold because it lost to Russia 0:2. Finland defeated the U.S. 4:3.

The last quarterfinal match guaranteed that exactly one Czechoslovak team would make it to the semifinals. Slovakia has won all five matches at the beginning of the olympic tournament while Czechia was only able to beat two underdogs, namely Italy and Germany. Nevertheless, it seems that the Slovak players still view the Czechs as "older brothers" who are supposed to win: Czechia remains the most likely team to beat Slovakia. So eventually the Slovaks lost 1:3.

The previous link also explains that the Czechs had to play with the goalie #3 Milan Hnilička because the goalie #1 Dominik Hašek returned home with an injury while the #2 goalie Tomáš Vokoun was identified, much like loop quantum gravity, to be inconsistent.

In the semifinals, Czechia will play Sweden and Russia will face Finland. Czechia is the only surviving team in the tournament that will defend the glory of North American ice-hockey. The previous sentence should settle the question whom the citizens of the 1st and 3rd most civilized country in the world, according to the data in the right column of this blog, should root for. ;-)

Segments vs. Summers

Update: Prof. Jim Miller will become the first serious candidate to replace Summers. In his letter to the Corporation, Miller not only correctly analyzes the events but he also promises that he will never surrender to the segments. If you like the idea, please feel more than free to write your own letter to the Corporation to support Jim Miller. ;-) I am too conservative and will probably wait for someone older - and someone who won't require an army of Schwarzeneggers as bodyguards. :-)

It has been about 20 hours since the Harvard community has learned about the resignation of the president. As you can imagine, it is sad news for me. On the other hand, as you could have noticed, all of us survived: it was actually a bittersweet day.



Figure 1: Harvard's opinion about Larry Summers on 2/21/2006. Segments excluded.

It is better that Summers has made this tough decision (almost) himself than if he were directly fired because of the desire of the segments.

Another advantage of the current situation is that Summers and his soulmates have a huge moral advantage over the segments. Virtually everyone seems to realize that the segments are the problem. It is very hard to find an article on the Internet that would support the segments. The segments are those who threaten the intellectual qualities and intellectual diversity of the oldest U.S. university as well as other schools. The segments are those who forced this exceptional president to resign. The segments should be deeply ashamed.

The Wall Street Journal discusses the differences between the creative scholars and managers on one side and the segments on the other side here. Thanks, Aaron S., for the link. Bloomberg also supports Summers and compares his job and the challenges with the challenges that the Clinton team had to face. The Crimson explains that outside FAS, the support for Summers has been strong. The donors are upset by the resignation, too. The American Thinker thinks that the Left has captured Harvard, but I think that they are wrong. Ben Shapiro calls the behavior of the segments a "travesty", a disgrace to the university, and a dramatic example of the totalitarian control that the campus left exerts on its administrators.

Hundreds of other articles can be found via news.google.com. The blogosphere has more colorful articles - such as The Crucifixion of the Truth.

Summers has not only a moral advantage but he still has four extra months in the office before he will enjoy his sabbatical. Four months is enough to finish some smaller projects and save some money by squeezing certain segments. In the case that you have not yet understood why The Reference Frame invites you to use the word "segment" as the ultimate yet politically correct insult :-), here is the crucial sentence in which Summers announced his decision:

• I have reluctantly concluded that the rifts between me and segments of the Arts and Sciences faculty make it infeasible for me to advance the agenda of renewal that I see as crucial to Harvard's future.

This may be a lost battle for Summers but it may become a victorious war for all of us, too. Wednesday 2/21/2006 was also the day on which the self-censorship imposed on all of us by the segments becomes invalid. Summers himself is free to say what he thinks and as far as I can see, the rest of us is free, too. The segments are no longer just obnoxious inhibitors of our intellectual activity; they became someone who can actually force others to resign. They are demonstrably dangerous people and all of us should be talking about these threats seriously and without any self-censorship whatsoever.

Figure 2: Students' opinion about Larry Summers on 2/21/2006.

Meet fifty Texas Democratic candidates at once

The Harris County Democratic Party and more than 20 social clubs are joining together for a Primary Kickoff and Roundup Rally in Houston on Saturday, February 25. The event will showcase the party's candidates just before the primary elections.

Among the speakers will be Chris Bell, Bob Gammage, Barbara Radnofsky, and David Van Os, and there will be over fifty other candidates for federal, state, and county offices in attendance. You'll have the opportunity to meet them all.

It's at Drexler's Barbecue in downtown Houston from 5-8 pm and is sponsored by the following:

* 1960 Democrats
* I-10 East Democrats
* Area 5 Democrats
* Battleground Democrats
* Bay Area New Democrats (BAND)
* Bellaire Democrats
* Braeswood Democrats
* Democracy for Houston
* Fort Bend Area Democrats
* Greater Heights Democratic Club
* Harris County Democrats
* Harris County Democratic Party
* Harris County Young Democrats
* Katy Area New Democratic Organization (KANDO)
* Kingwood Democrats
* Meyerland Democrats
* Northwest Crossing Area Democrats
* Oil Patch Democrats
* River Oaks Area Democratic Women
* San Jacinto Democratic Veterans Brigade
* Sharpstown Democrats
* Texas Progressive Populist Caucus
* West Houston Democratic Club
* West University Area Democratic Club

The cost is $5.00 and recommendations are highly recommended. RSVP to kellen dot wilson at sbcglobal dot net .

Skilling and Lay get thrown under the bus again

This week it was the former managing director of investor relations and corporate secretary:

The spotlight was largely on former Enron Chairman Ken Lay today as a former company executive accused him of repeatedly misrepresenting the company's financial health to investors, analysts and even employees.

Paula Rieker ... told jurors that in one case she even corrected Lay and he still continued to misrepresent the truth about Enron's retail business. ...

"I told Mr. Lay a significant amount of the earnings came from the sale of stock by Enron Energy Services and not from core activities," Rieker said, meaning it was one-time revenue that did not indicate EES was strong. She said Lay did not change his pitch. ...

She said she was "very bothered" by the company decision to continue to make EES look like a growth story in 2001 by shifting its losses to the more profitable trading division. She said when she complained, her boss (Mark) Koenig (who has previously testified for the prosecution) said "'You may not agree with it, but your job is to deliver the company message.'"

Rieker said she saw Lay mislead analysts by pretending not to know the name of the financial deal called Raptor that was unwound at a $1 billion hit to shareholders equity. She said Lay also misled analysts about why the company stopped charting the future contract value of the retail division.

...

One of the most dramatic moments of the day may have been one of the least significant legally.

Lay isn't charged with insider trading or with stealing from the company as it went into its death spiral. But prosecutor (John) Hueston showed a timeline including troubles at Enron in October and November 2001 that contrasted the company's ills with Lay's drawing millions out in cash.

While the timeline focused on things like the pension plan closing to employees who wanted to move stock, the cancellation of the holiday party, the failure of the Dynegy merger, it also showed Lay withdrawing $1 million here or $2.5 million there in cash from a revolving loan account with the company approved by the board in better times.

Lay withdrew $1 million the day the Dynegy deal died, which was the last hope of keeping Enron out of bankruptcy court. Lay's lawyer Bruce Collins asked Rieker on cross-examination if that amount wasn't just a drop in the bucket when hundreds of millions of dollars were being called in by Enron creditors at the same time but she said "No sir."

Rieker recalled for jurors how in February 2002 the board of directors was presented with a report that included Lay's stock sales for 2001, the year the company came apart.

"I learned that Mr. Lay had been selling stock back to the company in return for cash in excess of $70 million," she said. When Hueston asked about how the board of directors reacted, Lay's lawyer objected several times.

"They were outraged," Rieker finally answered.

Asked if she could recall what any specific board member reaction, Rieker said, "John Duncan exclaimed that 'Mr. Lay was using Enron as a damn ATM machine.'" By the time Rieker repeated that, because of an objection in mid-sentence, it appeared every juror was taking notes.

Rieker also bolstered some of the testimony given by Koenig about Skilling's involvement in altering earnings reports before they were made public.

She said she understood that in January 2000 and again July 2000 that Skilling ordered that earnings per share be increased. In January, she said it was done virtually overnight when they realized analysts were estimating earnings at 31 cents, rather than the 30 cents Enron almost reported.

In July 2000, she said, her boss told her Skilling ordered the earnings be raised a couple cents over the 32 cents they had planned. She said analysts and investors were told it was strong underlying performance that caused the hike to 34 cents.

The truth, she said, "would have really hurt the credibility of Enron and it would have hurt the stock price."

I took a bit more than the usual liberty with that excerpt because it reflects so clearly the simply bottomless hubris of Kenny and Jeffrey. Besides the usual "what made these men think they could get away with this" has to be "what did they think their former underlings were going to say once they had made a plea deal with the Feds"?

It's really too bad they can't get life in prison, isn't it ?

(I'm not a death penalty advocate.)

Locality and additivity of energy

I found most of these debates about the "doubly special relativity" kind of crazy, so let me write a few general words about locality and additivity of energy.

Every physical theory that is supposed to describe our universe or any other remotely similar universe must satisfy the law of locality, at least approximately. What does it mean? It means that if you're doing something in Washington, DC, it should not directly influence events in Boston, MA. Well, as you know, Washington, DC may influence events in Massachusetts indirectly but it takes a certain amount of time for the influence to spread.

According to special relativity, you need time "t=s/c" where "s" is the distance and "c" is the speed of light. But even if you assume that the Lorentz invariance is not exactly satisfied in your setup, it should be clear that locality will continue to hold.

The laws of nature don't admit action at a distance, and if they do, such instantaneous effects must be very subtle and indirect. Note that we are assuming that objects can exist within space without modifying the asymptotic structure of spacetime which also means that we assume that the spacetime has 3+1 dimensions or more.

What does locality mean in our formalisms that describe the real world? Classical physics may be described in terms of a classical action or a classical Hamiltonian. If you study a system that is composed from two separated subsystems that are far from each other, the action or the Hamiltonian decompose into two pieces:

• S = S1 + S2
• H = H1 + H2

Consequently, if you impose the condition that the action is extremized and S1 only depends on some degrees of freedom and S2 only depends on other degrees of freedom, you will see that the extremality of S is equivalent to the extremality of S1 and the extremality of S2.

Analogously, if you derive the classical equations from the Hamiltonian H, the degrees of freedom of the first subsystem will only be affected by the terms in H1 while the other degrees of freedom will only be affected by H2. The subsystems decouple. We know that such a decoupling must be possible, at least approximately for large enough separations.

What about the quantum theory? At the quantum level, the Hilbert space Hil must contain states that look like tensor products of states from Hil1 and Hil2. The wavefunctions are products of wavefunctions of the subsystems. And if we assume that the two subsystems decouple, it implies that the Hamiltonian that generates time evolution must be equal to the sum of two individual Hamiltonians.




Do you prefer the path integral approach? You will only recover locality if the space of configurations of the whole system includes the Cartesian products of the histories of the subsystem 1 and those of the subsystem 2. Moreover, the action must again satisfy

• S = S1 + S2

which means that the phase in the path integral also factorizes

• exp(iS) = exp(iS1) exp(iS2)

which means that the calculated wavefunctions will again factorize into the products from the individual systems, much like the probabilities - which is the correct way how probabilities of independent events should behave.

As you can see, there must exist some sort of additivity of the action or the Hamiltonian. In relativistic field theory, the action is written as an integral over the whole spacetime and the Hamiltonian is written as an integral over the whole space and the requirements of locality are therefore trivially satisfied. This is also true at the quantum level assuming that the theory is anomaly-free and satisfies some other consistency criteria.

If you have a relativistic theory, the Hamiltonian itself becomes the time-component of a vector in spacetime. Not surprisingly, the remaining components of the vector - the momentum - can be written as local integrals, too. They also satisfy the constraint that the momentum of a composite system equals the sum of the momenta of the subsystems.

In BFSS matrix theory, the clustering property is realized slightly differently than in quantum field theory. Composite systems are described by block-diagonal matrices: each diagonal block encodes one subsystem. The contribution of the block off-diagonal modes, that are high-energy non-local degrees of freedom doomed to stay in their ground states, is zero. It is still true that the wavefunctions of composite systems factorize and the action and/or Hamiltonian (and momenta) are written as sums.

Whenever locality and separation of a system into pieces is a good approximation, the additivity of the action or energy-momentum and/or the multiplicativity of the path integral phase or the wavefunction must be satisfied.

In local theories with systems split into subsystems, the additivity holds not only for the action, the energy and the momentum but for any other additively conserved quantity, much like for the entropy.

The text above should make it clear that we cannot gain anything by a nonlinear redefinition of the energy or the momentum. For example, imagine that you use a "pseudoenergy" and "pseudomomentum" that differ from the usual energy and momentum by an overall factor that depends on the energy. You can immediately see that such pseudoenergy won't be additive. Non-linear function of energy is guaranteed to be non-additive. This also means that the redefinition of the energy for composite systems will differ from the formula redefining the energy for its individual parts. Locality will be violated and voodoo will become commonplace. If you wish, feel free to do research in the space of completely generic non-local theories but be ready that voodoo is not quite compatible with science.

The only way how you can save locality is that you actually find a reason why it is preserved. The only plausible way to prove locality is to show the equivalence of your theory with a theory where the energy and the momentum are additive. Redefined formulae for energy and momentum that fail to be additive are always inferior.

There is no point in using them. Formulae that may look natural in terms of non-linear functions of the the ordinary additive energy or momentum generically lead to non-local effects and the non-locality is only suppressed if it is manifestly suppressed in the ordinary, additive variables.

In the text above, I was describing subsystems that are truly separated. This requires the interactions to disappear. In the real world, it must be true that the interactions go to zero as the distance becomes large. At shorter distances, the interactions always matter.

In quantum field theory, one can still write down all interactions in terms of an action that is manifestly local because it is the integral of a local Lagrangian. In principle, quantum gravity may force you to think about more general theories where the action is not exactly an integral of a local quantity. The effective actions are nearly guaranteed to have non-local terms in them. But it is still true that at even longer distances, these non-localities must go away.

If there is no point in non-linear redefinitions of the energy and momentum, is there a reason why we should think about quantum deformation of the Poincare or de Sitter or anti de Sitter symmetries? My answer is mixed. In some contexts - like AdS/CFT or dS/CFT - we have at least some reasons to think that the quantum deformation of the symmetries could be relevant, especially because of the finite number of certain degrees of freedom in both cases. But as far as I know, no one has found a way to formulate dynamical rules - in terms of an action or its generalization - that enjoy a quantum deformation of a symmetry in 3+1 dimensions or higher. (There are solvable examples in two dimensions.) So this field remains speculative in nature. More obviously, proposing quantum-deformed theories without any justification of the deformation and without any idea how dynamics could be defined looks like a vacuous game to me.

Some time ago we discussed an unusual type of a star-product that was discussed in the context of three-dimensional theories. Such a construction would be obviously unphysical in 3+1 dimensions or higher because the additive rules for the momentum vector are violated, together with locality. In three dimensions it is plausible to imagine that a localized object always has nonlocal effects - because it creates a deficit angle - but in 3+1 dimensions or higher, such a reasoning is prohibited.

There are various directions in which our theories may be generalized but all of these generalizations are much more compatible with the principles of locality - and the associated analytical structure of the amplitudes. For example, perturbative string theory satisfies all analytical rules normally derived from local quantum field theories despite the fact that the elementary objects in string theory are extended.

In non-commutative field theory, the star product of exp(ipx) and exp(iqx) is still proportional to exp(i(p+q)x); just the overall phase may be affected by the non-commutativity. This is important for approximate locality represented by the additivity of the energy-momentum vector.

There are many modifications of special relativity and calculus in the literature that are extremely brutal in nature and it is very questionable whether mathematically ugly and unmotivated theories that drastically violate basic laws such as locality should be considered to be physics.

Icecream lost

Well, unfortunately I have just lost an icecream bet against Cumrun Vafa. The president resigned in the middle of our class - and he announced his sad intent in a written speech. The Harvard Corporation needed about 0.2 seconds to evaluate Summers' resignation and "surprisingly", the resignation was accepted and a reply was immediately sent back before I returned from the class. Then I needed 2 minutes to write this text. Harvard can be very efficient, indeed.

I am partly joking. Of course that I realize that all these letters have been prepared a relatively long time ago, not today. It had to be so. The Corporation had to act responsibly and be prepared for various alternatives. And it is almost certain that the decision to resign was not purely Summers' own decision. He had to speak to the members of the board.

Summers has been - and still is - an exceptional president, visionary, manager, provocateur, and an unusually sharp thinker-in-chief. He should have had more freedom to realize his dreams. However, many of his plans have been realized and many others will be realized by another president who will inherit the oldest U.S. university. I am not too afraid about Summers' future. Harvard Corporation will have to find a new president who will replace Derek Bok, the interim president from July 1st, 2006. Good luck.

The latest events had to be equally difficult for Summers himself as the events from 2005 but they were less frustrating for most of his supporters like me because the criticism was no longer exclusively based on general political and philosophical dogmas. Various critics have invented a lot of dirt and nonsense about Summers himself. While I find most of this criticism vacuous and inappropriate, it is no longer questioning the freedom of speech and thought at Harvard.

I am sure that even though Summers has resigned, the battle for the academic freedoms was one of his victorious ones. He gave a very good example to others how they should not be afraid to stand behind their ideas and evaluate them according to the available evidence rather than according to the ideological pressure of their environment.

What it will be like ordering a pizza in 2010

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Primary Endorsements

Vince Leibowitz and Charles Kuffner and Greg Wythe and Eddie Rodriguez have posted theirs; mine follow (in the contested races) :

US Senate -- Barbara Ann Radnofsky

Governor -- Chris Bell

Lt. Governor -- Ben Z Grant

Agriculture Commissioner -- Hank Gilbert

US Congress, 1st -- no preference

US Congress, 7th -- Jim Henley and David Murff both earn my endorsement. The constituents of the Seventh Congressional District would be well served by either man.

US Congress, 10th -- Ted Ankrum

US Congress, 28th -- Ciro Rodriguez

Texas House, District 140 -- no preference

Texas House, District 146: Borris Miles

Texas House, District 147 -- Garnet Coleman

And it's not a contested primary, but you all ought to know who I support for Texas Attorney General by now. I'll add links to other blogland endorsements as I find them, and if anyone wants me to explain my picks, ask me in the comments.

Update: Stace Medellin adds his dos centavos. Nate chimes in. LFT and Cincinnatus have some pointed remarks on the governor's race, from opposite perspectives.

Update: I really should revise my "no preference' in CD-01 to recommend whom you should not vote for, and that is Roger Owen. He is apparently an unmitigated homophobe and more than a little flaky, and isn't worthy of support.

Update (2/22): Abram gets up on his soapbox. Fred injects the truth serum. Just Another Matt gives us his.

Superluminality sign constraints

Our friends have finished their paper about the constraints on the signs of various terms in the effective action that are required by causality, i.e. by the fact that the speed of light can't be exceeded, not even at non-trivial backgrounds.

These superluminality constraints are classically contained in the energy conditions, especially the dominant energy condition, but these Gentlemen start from a very satisfactory and fundamental principle, namely the condition of unitarity.

Doubly Special Relativity is just a change of variables

In a five-page-long highly efficient paper, Nosratollah Jafari and Ahmad Shariati show that the rules of the so-called "doubly special relativity" (DSR) to transform the energy-momentum vectors are nothing else than the ordinary rules of special relativity translated to awkward variables that parameterize the energy and the momentum.

In fact, there have been two main "subspecies" of DSR proposed in the literature, and our Iranian friends trivialize both of them. The DSR by Magueijo and Smolin is the simpler one.

Magueijo and Smolin demystified

Jafari and Shariati start with the realization that much like

• "p^m pⁿ g_mn"
  

is preserved by the Lorentz transformations in ordinary special relativity, a similar function

• "p^m pⁿ g_mn / ( 1 - L p⁰ )²"

where L is the Planck length - is preserved in the Magueijo-Smolin DSR. This leads them to define new variables for the energy momentum vector

• "pi^m = p^m / ( 1 - L p⁰ )"

and unless they have made a trivial error, they have shown that in terms of these new variables "pi^m", the DSR Lorentz transformations of the 4-vector reduce to the standard Lorentz transformations of special relativity. Note that all components of the energy-momentum vector have the same denominator in the redefinition which is why the direction in spacetime (or velocity) is preserved - it is only the overall magnitude of the 4-vector that is redefined.

Amelino-Camelia DSR

They also show that another version of the transformation rules, one that involves a lot of "sinh" and "cosh", is equivalent to ordinary special relativity, too. In this particular case, they find a non-linear redefinition of the generators of boosts instead of the energy-momentum vector itself. So far I have not checked this portion of the paper at all but I have not found a good reason to doubt that they are correct either.

In this Amelino-Camelia case, it is somewhat unclear whether the physical system is supposed to be invariant under the modified or unmodified boosts and what it exactly means for the system to be invariant under the modified boosts. But I guess that whatever answer we choose, we either obtain something that is equivalent to the conventional theories or inconsistent.

Conclusions

Consequently, there is no new physics in doubly special relativity, and the concept of doubly special relativity can't be used to explain why some physically sick theories such as loop quantum gravity fail to be Lorentz-invariant. Of course, this is no surprise for most physicists because everyone has always known that there can't be any fundamentally new theories that are just "partially" Lorentz-invariant. But still, it is useful to have an explicit set of formulae that prove that there is no new physics behind the papers about DSR. Note that the required field redefinitions are given by non-polynomial functions of the momenta which is why physics would look non-local in the coordinates that are dual to the bizarre DSR momenta instead of the standard ones.

What I still find a bit confusing is that I thought that the Amelino-Camelia DSR had the Poincare group that was a contraction of the quantum deformed AdS or dS symmetry. Quantum deformation looks like something different from a cheap redefinition of variables (or generators). But maybe this difference goes away in the limit of a vanishing cosmological constant, i.e. because of the contraction.

These doubts aside, DSR is certainly not the only example of an overhyped idea that is sold almost as a competitor to the whole field of high-energy physics or string theory but whose emptiness can be shown on one page or two.