Eurostrings 2006

This past week there has been a conference going on in Cambridge called Eurostrings 2006. It’s a bit like the annual “Strings XXXX” conferences, although about half the size and organized just by European institutions that are part of the European Superstring Theory Network, which since last year has been funded by a grant from the EU. Part of the conference consists of a celebration of Michael Green’s 60th birthday.

Most of the talks are already available online. There’s not much new being reported, but the talks include a nice review talk on topological strings by Robbert Dijkgraaf. There’s another talk on recent work on topological strings by Erik Verlinde, and a week earlier there was a conference in Munich devoted to the subject.

Nathan Berkovits talked about work in progress with Nikita Nekrasov on multi-loop amplitudes using his pure spinor formalism. This subject still seems remarkably confused, with Berkovits explaining that they have found a problem they still don’t know how to resolve: their regularization causes amplitudes with genus larger than 6 to vanish, violating unitarity. For commentary on yet another new suggested formalism for defining superstring amplitudes due to Warren Siegel and Kiyoung Lee, see this posting by Lubos Motl.

As part of the Green birthday celebration, John Schwarz gave a talk on String Theory Books. He reminisced about the writing of the two-volume book with Green and Witten (his outline refers to a “removed chapter”, and “broken vow”, what are those?). Evidently the book was written in 9 months back in 1986, a truly heroic effort given its size. Last Monday, Schwarz finally finished up a new textbook on string theory, written with Katrin and Melanie Becker and entitled “String Theory and M-theory: A Modern Introduction”. They started writing back in February 2005, planning a 350 page book to be completed by the end of September, but ended up just last week completing a 729 page book. From the table of contents it looks like GSW abbreviated and updated, containg more modern material on branes, dualities, black hole entropy, flux compactifications and gauge/string dualities. It seems rather peculiar that flux compactifications and the landscape get a whole chapter, whereas AdS/CFT is dealt with in one section of one chapter. All in all, comparing the new book to the old one, twenty years later the subject has become a lot more complicated, a lot uglier, and the prospects for using it to predict anything about the standard model have vanished.

The Schwarz talk also has a link to a video of a Berlitz commercial featuring a German radio operator misunderstanding someone radioing in a distress call that they were sinking (the German hears this as “thinking”). I can’t at all figure out what this has to do with Schwarz’s talk. Is string theory making a distress call as it is sinking, but no one understands this?

Victor Rivelles attended, and has blog entries here, here and here. He reports on a talk by my fellow Princeton student Costas Bachas about using string theory techniques to solve capillarity and wetting problems, then comments that “If LHC provides no proof to string theory string theorists will not lose their job, they can just change to applied string theory!”

Posted in Uncategorized | 14 Comments

The Templeton Foundation: A Skeptic’s Take

Science writer John Horgan has just written a piece about the Templeton Foundation that is causing a bit of a ruckus. It first appeared in The Chronicle of Higher Education, and is also posted a the Edge web-site, where perhaps some further discussion of it will appear.

Horgan participated in a program held at Cambridge as a Templeton-Cambridge Journalism Fellow in Science and Religion, an all-expenses paid gig that came with an additional $15,000 that made it hard to turn down. He had very mixed feelings about the experience, and explains these in detail.

The financial scale on which Templeton operates is unparalleled in this area. As in Horgan’s case, the people they invite to participate in their programs are often offered a lot more money than usual for this kind of thing. The foundation has an endowment of $1.1 billion, and is funding more than 300 projects at the rate of $60 million/year, a rate they intend to double. By comparison, the total NSF budget for supporting theoretical physics is also about $60 million/year. The sheer number and diversity of organizations using Templeton money to promote bringing science and religion together is staggering. I keep finding new ones at various places around the web, and also have yet to run into any organization trying to bring religion into science that isn’t getting Templeton funding.

One new Templeton-funded project is called Foundational Questions in Physics and Cosmology, and has a very illustrious advisory board of physicists. It has just finished accepting proposals for a first round of grants to total $2 million, and has received a 172 proposals, totalling $23 million, from top institutions including Caltech, Harvard, MIT, Princeton and The Institute for Advanced Studies, Stanford, UC Berkeley, Oxford, and Cambridge. Sean Carroll (who turned down Templeton money since he disagrees with what they are trying to promote) has a posting about this, including a guest blog entry and discussion with Anthony Aguirre, who is one of the physicists running the project.

The ethical questions involved in the question of whether to accept money from a source one is not completely happy with are not at all straight-forward. One can sensibly argue that there is nothing wrong with taking money from someone whose goals one disagrees with, as long as they let you do what you want with it, and one isn’t forced to further such goals. On the other hand, publicly associating oneself with an institution to some extent lends ones credibility and prestige to the institution and inherently furthers their goals. It’s also true that money talks, and a large amount of money talks loudly. Many scientists in recent years have probably ended up doing one thing or another that they wouldn’t otherwise have bothered to get involved in because Templeton money made it rather attractive.

There seem to me to be several different things about Templeton to be wary of. One is that the foundation’s leader, Sir John Templeton, is in the process of turning over control of the organization to his son, John Jr., who has a much more politically right-wing, evangelical Christian, point of view than his father. Even if one has no problems with what the foundation has done in the past (e.g., it has not supported creationism), this doesn’t mean it won’t change what it does in the future.

I personally happen to think that bringing religion into physics is inherently a bad idea. Whatever one’s view of religion is, it is inherently a quite different thing than science, and at a time when standards of what is science and what isn’t are under attack, a blurring of the distinction between science and religion may be very dangerous. Much of what Templeton supports seems to me rather silly, but not much of a threat to anything important. For example they are funding a project in Vienna that will bring together physicists, philosophers and theologians to study the foundations of quantum physics. I don’t believe the theologians will be much help here, but they’re not likely to cause much harm. On the other hand, the large amount of Templeton funding promoting symposia devoted mostly to pseudo-science like this one on the Multiverse and String Theory is much more worrying.

Posted in Uncategorized | 37 Comments

Back

Had an amazing trip, which involved several days of travel through hundreds of miles of spectacular sand dunes in four-wheel drive vehicles operated by impressive Tuareg drivers (no camels). This put me and the group I was traveling with somewhere in between Dirkou and Bilma, about at the center of the shadow seen in this picture:

Eclipse Shadow

At some point I may post some links to other pictures. In a day or so after I deal with a couple hundred e-mails we’ll return to your regularly scheduled programming.

Update: Fred Bruenjes was at the same eclipse camp in Niger, and has a report on the eclipse here. He also tells about traveling to the site, taking a more leisurely route than the one taken by the group I was with.

Posted in Uncategorized | 20 Comments

Hiatus

I’m leaving tomorrow night on a trip that will take me away from internet access for a week or more. During this time I won’t be posting anything, or able to manage the comment section, so I’ll be shutting off comments late tomorrow afternoon, turning them back on when I’m back on April 4th.

The trip will take me to the middle of the Sahara, in Niger, where I hope to see the total solar eclipse next Wednesday. I’d like to be able to claim that this is some sort of scientific expedition, involving perhaps testing GR by measuring the deflection of starlight during the eclipse. But that’s not the case; this is really just an excuse to go to an exotic location for a much-needed vacation. I thought for a moment about renting a satellite phone with a modem, and blogging from the desert, but decided that would seriously impinge on the important vacation aspect of this trip.

Another reason for the hiatus is that I haven’t been able to come up with an inspired idea for an April 1 posting, and this gives me an excuse for giving up on trying to do that again this year. If I get any good pictures, maybe I’ll finally get around to putting something more visually appealing here.

Posted in Uncategorized | 21 Comments

Letter From Schroer

Bert Schroer has sent me a very long and interesting comment for posting here. I’ve put it into a separate web-page. It includes both a lot of history and many different ideas. Unfortunately I don’t have the time right now to write much about it in response, but just will make one point about the part that he explicitly addresses to me.

Schroer claims that geometric methods in QFT have so far only been useful in dealing with free fields in a fixed background gauge field or metric. This is largely, but not completely true. Most of our reasons for believing the standard model are based on perturbative quantization of gauge fields, and for this it’s true that geometrical methods are not strictly necessary. But for QCD, we need a non-perturbative quantization of the gauge fields, and here lattice QCD is the best we’ve got. It is based upon discretizing a geometrically formulated path integral, preserving as much of the gauge field geometry as possible. My own guess is that there is still a lot to be learned about non-perturbative quantization of gauge fields, based upon the geometrical formulation of the problem given by the path integral approach and I have been working on speculative ideas of how to do this (some of which even involve gerbes and algebraic geometry…). This is still work in progress, maybe I’ll someday find it really can’t work, but for now I’m quite optimistic.

There’s also a new survey paper on QFT from Fredenhagen, Rehren and Seiler. The authors discuss the current state of understanding of QFT, with some points of overlap with Schroer. Like Schroer, they also discuss string theory in detail, and are critical of the inability of the string theory research program to come up with precise statements about what the theory is supposed to be. They are however, much less forceful in their criticisms than Schroer.

Posted in Uncategorized | 14 Comments

New Top Quark Mass

Via Tommaso Dorigo of the CDF collaboration, the news that the Tevatron Electroweak Working Group has released a new analysis of combined CDF and D0 data with the most accurate result so far for the top quark mass: 172.5 +/- 2.3 Gev. Last summer this value was at 174.3 +/- 3.4 Gev (see a posting here), an improvement over the earlier value derived just using Run I data of 178.0 +/- 4.3 Gev.

The paper describing these results is available now here, and will soon be on the arXiv as hep-ex/0603039. This new result represents a determination of the top quark mass to 1.3% accuracy, and the paper claims that further Run II data should ultimately allow an accuracy of better than 1%.

For a talk about the significance of the top quark mass, see here.

Posted in Uncategorized | 28 Comments

2005 Topcites

The SLAC SPIRES yearly list of most frequently cited papers in 2005 is now available. I commented recently on what this was likely to show, quantifying the intellectual collapse of string theory since 1999.

There are exactly three post-1999 particle theory papers among the top 50 in the list. Two of these are about flux compactifications and have moved up significantly since last year reflecting the increasing popularity of landscape studies. At number 18 (up from 29) is the KKLT paper from early 2003, and at number 34 (up from 54) is an earlier paper from 2001 by Giddings, Kachru and Polchinski. The only non-landscape post-1999 paper to crack the top 50 is the 2002 Berenstein, Maldacena and Nastase paper on PP waves (which is part of the AdS/CFT story). It just barely makes it at number 49 (down from 32 last year).

The highest ranked post-2003 paper is the Arkani-Hamed and Dimopoulos 2004 paper on split supersymmetry. It’s at number 106, with a total of 103 citations.

There’s also a new 2005 All-time topcited list. Maldacena’s AdS/CFT paper from 1997 remains very near the top, with 3881 citations. There is nothing post-1999 on this list, which includes the top 186 papers. If recent trends continue indefinitely, it seems entirely possible that no post-1999 particle theory paper will ever make this all-time top-cited list, allowing historians of science to conclusively pinpoint the death of particle theory as having coincided fairly precisely with the end of the 20th century. This is optimistically assuming people lose interest in the landscape. It is also possible that landscape studies will come to dominate the field, with landscape papers then climbing up into the all-time topcited list. This doesn’t really change the conclusion about the death of particle theory.

Posted in Uncategorized | 18 Comments

2006 Templeton Prize

The 2006 Templeton Prize of $1.4 million was awarded yesterday to cosmologist John Barrow. Barrow is the author of about 400 scientific articles and nearly 20 popular books. In recent years, one of his interests has been the possibility of time-variation of fundamental constants. At a press conference in New York yesterday, he said that new data on quasars expected within two months may provide evidence of such variation.

Science and Spirit has an article by Barrow written for the occasion and called The Unexpected Universe. It also has a report on the press conference that goes on at length about the string theory anthropic landscape and credits Barrow (and Tipler) with writing a “highly influential book for the interface between science and religion” back in 1986 entitled The Anthropic Cosmological Principle. The report includes the following gibberish:

String theorists also assume that other universes, which collectively compose a “multiverse,” exist in other dimensions outside of our observational parameters. Our own very limited experience suggests that finely tuned universes might be more likely to exist than more randomly constructed universes, at least over the long term. If this is true, then fine-tuning may be a guide that cosmologists can use to one day locate and observe an alternate universe.

Barrow himself however doesn’t seem to have much to say about the string theory landscape.

Maybe if Leonard Susskind hadn’t said unfriendly things about having no use for religion in his recent book, he could have been $1.4 million richer instead of Barrow. The New York Times headlines its story about this Math Professor Wins a Coveted Religion Award. A mathematician friend of mine is kind of outraged at this and wants to write to the Times to complain about the description of Barrow as a “math professor”.

Posted in Uncategorized | 21 Comments

Three-year WMAP Data Now Out

Data from the second and third year of the WMAP satellite experiment has just been released a few minutes ago. There a press release and other general information page. The scientific paper explaining what this new data tells us about cosmology is Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for Cosmology. This is a good time to admit that I’m no cosmologist, and thus not the person to get information from about the significance of these results. However, I expect some of the earliest informed discussion of them should take place on various blogs, and I’ll be linking to those as I see them.

Update: Comments from Sean Carroll and Steinn Sigurosson. Discussion at CosmoCoffee and Bad Astronomy and Universe Today Forum. Also a posting from Lubos. I’m no expert here, but Lubos’s comments seem to me to be nonsense (I find it hard to believe that in the three-year data set they’re resolving structure 100 times smaller than in the first year, and I think he’s just completely wrong to say that this data rules out ekpyrotic or cyclic models).

Update: Christine Dantas also has more about this.

Update: Amazingly, Lubos still is maintaining that the 3 year results have 100 times better angular resolution than the 1 year results. This kind of fanatical inability to ever admit that one was wrong about something goes a long way towards explaining the current state of string theory.

Posted in Uncategorized | 19 Comments

George Mackey 1916-2006

It was sad to see an announcement today on the Harvard math department web-site of the death earlier this week of emeritus Harvard professor George Mackey.

Mackey’s mathematical work is dear to my heart, since its central concern is the relationship between quantum mechanics and representation theory. He began his career in functional analysis, getting his Ph.D. in 1942 under Marshall Stone. Back in 1930 Stone and von Neumann had proved a crucial theorem about quantum mechanics, a theorem which essentially says that once you choose Planck’s constant, up to unitary equivalence there is only one possible representation of the Heisenberg commutation relations. This uniqueness theorem is what allows one to just define quantum theory in terms of the operator commutation relations, and not worry about which explicit construction of the representation of these operators on a Hilbert space one uses. The theorem is only true for a finite number of degrees of freedom, and thus doesn’t apply to quantum field theory, one reason why quantum field theory is a much more subtle business than quantum mechanics. Stone and von Neumann put their work in the context of representation theory of the Heisenberg group (actually due to Weyl) and this was of great interest to mathematicians since it was one of the first results about the representation theory of non-compact Lie groups. For an excellent history and introduction to this subject, see the paper A Selective History of the Stone von-Neumann Theorem by Jonathan Rosenberg.

Mackey seems to have been the person who gave this theorem its name, in his important paper of 1949 “A Theorem of Stone and von Neumann” which generalized it. Over the next few years Mackey extended this much further in a series of papers on induced representations (representations of a group G “induced” from representations of a subgroup H). The foundation of this work is now known as the Mackey Imprimitivity Theorem, and it provides a powerful tool for studying representations of a large class of non-compact groups, including especially semi-direct products.

Mackey was a wonderful expositor, and over the years I’ve learned a great deal from some of his expository books and papers. His 1963 monograph Mathematical Foundations of Quantum Mechanics is very readable. In 1966-67 he gave a course at Oxford on representation theory and its applications, the notes of which were published in 1978 as Unitary Group Representations in Physics, Probability and Number Theory. This is a fantastic book, covering a wide range of topics relating quantum mechanics, representation theory and even number theory. A later collection of expository material, from 1992, was published by the AMS as The Scope and History of Commutative and Non-Commutative Harmonic Analysis. It contains what is perhaps the best of his expository work, an historical survey first published in the AMS Bulletin in 1980 entitled “Harmonic Analysis as the Exploitation of Symmetry”.

While I never took a course from Mackey, I did get to talk to him on several occasions. I especially remember a conversation in which he described his technique for speaking French during the time he spent in France. He decided to speak his own rationalized version of the language, eliminating extraneous and confusing structure like genders of nouns. Not clear what the French thought of this. He was an original, and I’m sad to hear he’s no longer with us.

Update: Stephanie Singer has put up copies of letters from Mackey on her web-site. A memorial service for Mackey will be held in Cambridge on April 29.

Posted in Obituaries | 9 Comments