Not Even Wrong

Today’s second most viewed article in Newsweek is an interview with Steven Weinberg about what we’ll learn at the LHC. Unfortunately it almost immediately turns into a discussion about religion and is linked to on the Newsweek site as Will Physicists Find God? The interviewer wants to know whether the Nobelist will be willing to reconsider his well-known atheism based on what is found at the LHC. Weinberg does a good job of answering these questions politely and sensibly. He gets a bit into philosophy of science, noting that the hypothesis of the existence of God is testable (in the same sense that string theory is testable), since thunderbolts coming out of the sky and striking atheists dead would give strong evidence that He (or She) exists.

Sean Carroll, quoting from a book by David Deutsch on parallel universes, attacks Weinberg as not understanding how science works in a blog posting about Science and Unobservable Things, and in a discussion with John Horgan at Bloggingheads entitled Cosmic Bull Session. He specifically is critical of a claim by Weinberg that “the important thing is to be able to make predictions”, arguing that such a statement is “going a bit too far.”

This month’s Discover magazine has a cover story on theories of what happened before the Big Bang. The article begins with St. Augustine speculating on what God was doing before the first day of creation, then moves to discuss the work of several modern “cosmology heretics”. The discussion doesn’t include the work of the Bogdanovs, but does cover three such theories, from Steinhardt and Turok, Carroll and Chen, and Barbour, ending up with a discussion of the crucial problem of testability of such theories. Steinhardt and Turok are rather concerned about this, and point to one negative prediction (shared by many cosmological models) that they can make: effects of gravitational waves will not be seen in the CMB polarization. Carroll and Barbour on the other hand don’t seem to have a problem with not being able to predict anything, with Barbour described explicitly as having “no way to test his concept of Platonia.”

For more recent research on the multiverse, see philosopher Klaas Kraay’s Theism and the Multiverse, where he argues that:

theists should maintain that the world God selects is a multiverse. In particular, I claim that this multiverse includes all and only those universes which are worth creating and sustaining. I further argue that this multiverse is the unique best of all divinely-actualizable worlds.

Tomorrow I’ll be in Las Vegas, on my way to southern Utah, so will miss a couple of math-physics media events taking place in Paris. At 2pm on Sunday, Lubos Motl will be appearing at the France Television booth at the Salon du Livre, together with the Bogdanov brothers, to sign copies of his new book L’equation Bogdanov: Le secret de l’origine de l’Univers?. In other Lubos news, I recently heard a rumor that he is now the scientific advisor to the president of the Czech republic.

On Monday, a day-long symposium on the topic of how mathematics and physics are covered in the press will be held at the Institut Henri Poincare. One focus of the symposium is the celebrity exceptional Lie group E8, which last year kicked up media-storms for both the classification of unitary representations of its split real form, and for Garrett Lisi’s attempt to use it for unification. Jean Iliopoulos will be speaking on the topic of the hopes and controversies surrounding string theory, and I’d be curious to find out what he has to say about this.

Update: More information about the E8 talks here, Lubos’s impressions of Paris here.

The past few weeks I’ve often been going down to the IAS in Princeton on Thursdays to hear talks given as part of the special program there this semester in mathematics. These talks included a series of five talks by Witten; notes from David Ben-Zvi and Sergei Gukov are available here.

The first three talks concentrated on the existence of a very special superconformal six-dimensional QFT, and information that could be derived from what is known of its properties. Such a theory is an inherently quantum object, lacking a usual sort of classical limit or Lagrangian formulation. Witten compares it to the holomorphic conformal field theory that appear as “square roots” of the WZW model. These field theories are closely related to the representation theory of loop groups and at the core of a several important mathematical developments of the last couple of decades. The mathematical significance of the six-dimensional theory remains much more mysterious, and Witten argues that understanding this mystery is a very worth goal for both mathematicians and physicists. . For more about this, see the article Conformal Field Theory in Four and Six Dimensions, based on his lecture at the Oxford conference in honor of Graeme Segal’s 60th birthday back in 2002. Taking the six dimensions to be the product of a torus and a four dimensional space, the existence of such a superconformal six dimensional theory implies an SL(2,Z) symmetry of N=4 Super-Yang-Mills on the four dimensional space. This includes the famous Olive-Montonen non-abelian electric-magnetic symmetry that is responsible for Langlands duality in Witten’s 4d QFT approach to Geometric Langlands.

The last two talks of the series dealt with a different topic, boundary conditions in N=4 SYM. Taking this theory on the half-space with boundary conditions, one can ask about the implications of non-Abelian electric-magnetic duality for these boundary conditions. Witten has recently been working on this subject with Davide Gaiotto, he’ll be talking about it later this month at a Stony Brook symposium in honor of C. N. Yang and Jim Simons, and I assume a paper will appear sooner or later. In his IAS lectures Witten was talking to mathematicians and arguing that “universal” operations (ones that can be done uniformly for all Riemann surfaces) in geometric Langlands should all come from the properties of these boundary conditions. Note that in this work what appears is the full N=4 SYM theory, not just the topological twisted version. This theory plays a central role in AdS/CFT, so if new information about its physics arises from this study, this should be directly interesting for physics, although Witten did not discuss this in his talks.

The two sorts of boundary conditions that get related by duality are analogs of Neumann and Dirichlet boundary conditions. The Neumann boundary conditions involve superconformal 3d QFTs, examples of which were studied by Intriligator and Seiberg in their 1996 paper Mirror Symmetry in Three Dimensions. Witten has previously worked on this kind of thing in the Abelian case, see here.

During these visits to the IAS I got the chance to meet Meng-Chwan Tan, who is there in the Physics group this year. He has been working on a different QFT approach to geometric Langlands, one that is purely two-dimensional and based in conformal field theory, using (0,2) sigma models on flag manifolds, and has just posted a the revised for publication version of his paper on the subject here. This is much closer to the approach to geometric Langlands via conformal field theory that Edward Frenkel has described here.

In other geometric Langlands news, there was a workshop on Homological Mirror Symmetry recently in Miami, with notes from many of the talks available here (and a blog posting by Joel Kamnitzer here). And there’s another one (notes here from David Ben-Zvi) going on this week at the IAS. I better stop now, go and get some sleep so I can head down there tomorrow morning to catch the last day of it.

The 2008 Templeton Prize was announced today. It goes to Michael Heller, a Polish cosmologist, philosopher and Catholic priest, for “sharply focused and strikingly original concepts on the origin and cause of the universe.” The full name of the Templeton Prize is the “Templeton Prize for Progress Toward Research or Discoveries About Spiritual Realities” Its goal is to promote bringing science and religion together by awarding a prize of 820,000 pounds sterling, the single largest award given to an individual. Prince Philip somehow gets into the picture too, since he will be presenting the prize to Heller in a private ceremony at Buckingham Palace in early May.

In recent years Heller has been interested in non-commutative geometry as way to study quantum gravity and cosmology. According to Heller, the crucial question of cosmology is “Can the Universe Explain Itself?”, and associated with the awarding of this prize, the Templeton Foundation will be hosting a discussion of the associated question “Does the Universe Need to Have a Cause?”.

The Templeton press materials describe Heller as “initiating what can be justly termed the ‘theology of science.'” His nomination for the prize says that:

It is evident that for him the mathematical nature of the world and its comprehensibility by humans constitute the circumstantial evidence of the existence of God.

I’m rather dubious about the way Heller mixes theology, philosophy and cosmology, but, unlike much harder-nosed physicists these days, at least he seems to recognize the problems with the Multiverse.

Heller intends to use the prize money to create a Copernicus Center in Cracow to further research and education in science and theology.

The String Vacuum Project, described as “a large, multi-institution, interdisciplinary collaboration”, that has been established over the last few years, is having its Kick-Off Meeting next month at the University of Arizona. This group had submitted grant proposals to the NSF for funding of such a project in the past, but I don’t know if they ever managed to get NSF or other funding. They motivate the project by claiming that

Given that relatively large numbers of string vacua exist, it is imperative that string phenomenologists confront this issue head-on…

In this context “relatively large” involves numbers like 10⁵⁰⁰, 10¹⁵⁰⁰, etc.

Bert Schellekens has a web-site devoted to promoting the Anthropic Landscape, where he argues that

The String Theory Landscape is one of the most important and least appreciated discoveries of the last decades.

Besides the web-site, he has slides from two general talks on-line (here and here). In the talks he compares string theorists to the famous Emperor parading in no clothes, except what he is criticizing is those string theorists who have been unwilling to acknowledge the existence and importance of the anthropic landscape. He’s critical in particular of

those people claiming that they have always known that String Theory would never predict the standard model uniquely, but that they did not think this point was worth mentioning.

His modernized version of the fable of the Emperor goes as follows:

Many years ago, there lived some physicists who cared much about the uniqueness of their theories. One day they heard from two swindlers that they could make the finest theory which was absolutely unique. This uniqueness, they said, also had the special capability that it was invisible to anyone who was stupid enough to accept anthropic thinking.

Of course, all the townspeople wildly praised the magnificent unique theory, afraid to admit that anthropic thoughts were inevitable, until Lenny Susskind shouted:

“String theory has an anthropic landscape”

It’s not clear who he would identify as the “two swindlers”….

According to Schellekens, the “string vacuum revolution” is on a par with the other string theory revolutions, but most people prefer to overlook it, since it has been a “slow revolution”, taking from 1986-2006. The earliest indications he finds is in Andy Strominger’s 1986 paper “Calabi-Yau manifolds with Torsion”, where he writes:

All predictive power seems to have been lost.

and in one of his own papers from 1986 where the existence of 10¹⁵⁰⁰ different compactifications is pointed out.

Schellekens claims that “string theory has never looked better”, but he completely ignores the main question here, the one identified by Strominger in 1986 right at the beginning. If all predictive power is lost, your theory is worthless and no longer science. What anthropic landscape proponents like him need to do is to show that Strominger was wrong; that while string theory seems to have lost all predictive power, this is a mistake and there really is some way to calculate something that will give a solid, testable prediction of the theory. The String Vacuum Project is an attempt to do this, but there is no evidence beyond wishful thinking that it can lead to a real prediction. Schellekens has worked on producing lots of vacua and describing them in a “String Vacuum Markup Language”, and in his slides describes one construction that involves 45761187347637742772 possibilities. These possibilities can be analyzed to see if they contain the SM gauge groups and known particle representations, but this is a small number of discrete constraints and there is no problem to satisfy them. The problem is that one typically gets lots and lots of other stuff, and while one would like to use this to predict beyond-the-SM phenomena, there is no way to do this due to the astronomically large number of possibilities.

He lists goals for the future (“Explore unknown regions of the landscape”, “Establish the likelihood of SM features”, “Convince ourselves that the standard model is a plausible vacuum”), but none of these constitutes anything like a conventional scientific prediction that would allow one to test to see if what one is doing has any relation to reality. In the end, he comes up with the only real argument for the String Vacuum Project and other landscape research, that of wishful thinking:

… and maybe we get lucky.

Update: There’s a story about the String Vacuum Project in this week’s Nature by Geoff Brumfiel. It includes skeptical comments from Seiberg and yours truly, as well as Gordon Kane’s claim that:

evidence supporting string theory could emerge “within a few weeks” of the [LHC]’s start-up.

Update: At the blog Evolving Thoughts, there’s a discussion of whether theoretical physicists have now taken up a “stamp-collecting” model of how to do science. I point out that this is stamp-collecting done by people who don’t have any stamps, just some very speculative ideas about what stamps might look like.

Larry Fleinhardt, the fictional Caltech string theorist in the TV show Numb3rs, has decided to give up on string theory for now and become a phenomenologist. According to the show’s co-writer Nick Falacci:

Like real-life physicists, Fleinhardt hit a roadblock trying to create an 11-dimensional supergravity theory.

So, he will be joining the DZero collaboration at the Tevatron and work on the search for the Higgs. According to Fermilab Today, an office for Fleinhardt at Fermilab has already been created.

It’s not clear if Ed Witten or his brother Matt had anything to do with this…