It’s late tonight and I have to prepare a class for tomorrow, so I don’t have time now to figure out what is going on here. But if you want to see something really strange, take a look at Susskind’s latest, together with the revised version of an earlier paper.
Another new paper this evening is Witten’s latest. This looks quite interesting, but definitely will take some serious effort to understand.
A week or so ago I wrote up as an April Fool’s joke a posting claiming that the Stanford theoretical physics group was joining a new Templeton foundation devoted to religion and science. At the time I had no idea of the degree to which Templeton-funded pseudo-science has infected mainstream cosmology. This joke turned out to be much closer to reality than I had imagined. In my quick research before writing it, I had missed the fact that the Templeton Foundation two years ago organized a symposium at Stanford on the topic of Universe or Multiverse?. The participants, presumably funded by Templeton, included a large fraction of the senior Stanford ITP faculty (Dimopoulos, Kallosh, Linde, Susskind). Someone also wrote to me to tell me that Gerald Cleaver had spent a sizable amount of time at Stanford at Susskind’s invitation, something I was completely unaware of when I picked him to co-direct the Templeton institute with Susskind. Finally, Mark Trodden reported in the comment section that “When I was out at LCWS04 at Stanford a couple of weeks ago I was dismayed to find out that there was a Templeton conference going on at the same time and that a number of prominent people were attending it rather than LCWS04.”
One of the other attendees at the Templeton conference was Alexander Vilenkin, and yesterday Lubos Motl had a report on Vilenkin’s talk at Harvard on “Probabilities in the Landscape”. Lubos explains in some detail what a load of pseudo-scientific nonsense this all is, and I’m in complete agreement with him, down to his last paragraph about how “Finally, I am sure that various people who have a similar opinion about the anthropic thinking will use this admitted frustration as a weapon against string theory.” Certainly. By the way, Vilenkin’s research is funded by a Templeton grant.
It seems that Cambridge University Press will be publishing a volume this year also entitled “Universe or Multiverse?” based on the Stanford symposium. It’s being edited by Bernard Carr, a professor of Mathematics and Astronomy at Queen Mary College in London. He’s the recipient of a Templeton grant for a project entitled “Fundamental Physics, Cosmology and the Problem of our Existence”. When he’s not working on cosmology and religion, he is President of the Society for Psychical Research, which investigates poltergeists, parapsychology, survival after death, etc. You couldn’t make this stuff up. “Universe or Multiverse?” will include as least one sensible article, Lee Smolin’s Scientific Alternatives to the Anthropic Principle, which explains clearly why the Anthropic Principle is not science.
Another participant in the Stanford symposium was Robin Collins, and he’s contributing an article on “A Theistic Perspective on the Multiverse Hypothesis” to the Cambridge volume. He’s supported by the Center for Science and Culture of the Discovery Institute, a right-wing organization dedicated to promoting “Intelligent Design” research. The Discovery Institute has just started up a new weblog devoted to Intelligent Design called Intelligent Design The Future which has drawn scorn from (among others) Sean Carroll and Jacques Distler. Jacques claims to have fallen off his chair laughing at this posting with its claim that “mainstream physics is now quite comfortable with design in cosmology” and question “Why should inferring design from the evidence of cosmology be scientifically respectable, but inferring design from the evidence of biology be scientifically disreputable?”, but again I’m with Lubos that this is not funny. Actually it’s scary.
It’s becoming increasingly clear that the theory of evolution is under concerted and well-funded attack in the United States by a wide array of religious fanatics and pseudo-scientists, who are doing everything they can to stop the teaching of evolution in US schools and promote the pseudo-science of Intelligent Design. This is a fight that scientists need to join, but the extent to which pseudo-science has already infected mainstream physics and cosmology is becoming dangerous and is going to make it very difficult to effectively answer the Intelligent Designers. Susskind is giving a talk at Brown soon entitled The Cosmic Landscape: String Theory and the Illusion of Intelligent Design. Unless he’s gotten even crazier than I would have imagined, I guess he’ll be claiming that the string theory landscape/anthropic principle stuff he has been pushing only appears to support Intelligent Design. Behind it all is not an intelligent designer, but a wonderful physical theory called string theory. But the reason Intelligent Design is pseudo-science is that it is a non-predictive framework. It doesn’t predict anything, so you can’t test it and show that it is wrong. This is exactly the situation that string theory is in these days, and, for the life of me, I have no idea what response physicists can now honestly make to someone who says: “Look, you have a non-predictive framework involving a very complicated and incomplete mathematical structure that you believe for emotional and sociological reasons. I’ve got a different non-predictive framework tracing everything back to an Intelligent Designer, and I think mine makes more sense than yours.”
Science magazine has an article this week entitled High Energy Physics: Exit America?. It describes the US HEP budget situation, and gives details of the probable cancellation of the BTeV experiment. Evidently neither Michael Witherell, the Fermilab director, nor any of the physicists working on BTeV, had any idea this was going to happen until the day the FY 2006 budget was released.
The Science article is a lot more pessimistic about the future of high energy physics in the U.S. than any of the public reports you will read produced by the US high energy physics community, but it is also a lot more realistic. The underlying reality is that after the Tevatron stops operations in 2010 (because it can’t compete with the LHC), for the first time in the history of modern physics there will be no machine operatiing at the high energy frontier in the US. Fermilab is planning an active neutrino physics program, but this will be much more limited in scope than what the lab is doing today and has been doing since its founding.
The only plan on the table for the US to get back into the high energy accelerator business is the International Linear Collider (ILC), but the question of how such a machine would be financed, and whether it would even be constructed in the US at all, remains up in the air. In a very real sense, the future of experimental high energy physics in the US after 2010 is a very large question mark.
Edward Witten is in Canada this week, giving a series of lectures at the Fields Institute, the mathematics institute at the University of Toronto. He’s also giving a public lecture at the Perimeter Institute in Waterloo.
The first of his lectures in Toronto, on the topic of Relativistic Scattering Theory is now available on-line. It’s a nice, simple explanation of scattering theory, using the “geometric quantization” point of view about quantum field theory. For a quantum theory of a real scalar field, one chooses a complex structure on the space of solutions of the free field equation, making this a priori symplectic infinite dimensional manifold actually a Kahler manifold. Witten’s next two lectures in Toronto will be on “Gauge Symmetry Breaking” and “The Quantum Hall Effect”.
I’m curious what he’ll be promoting in the public event at Perimeter on Wednesday. Will it be string theory? Will anyone ask him about the appalling nonsense his fellow string theorists were spouting there all last week?.
Stanford University will officially announce later today the founding of a new research institute, with major funding from the John Templeton Foundation. Many of the faculty and research staff of the new institute will come from the present Institute for Theoretical Physics which will be shutting its doors.
Co-directors of the new institute will be Stanford faculty member Leonard Susskind, and Gerald Cleaver, who is currently head of the Early Universe Cosmology and Strings Group at Baylor University. Susskind, who is one of the co-discoverers of string theory, has in recent years been the most prominent promoter of the theory of the “multiverse”, which he describes in a recent interview. Later this month he will be giving the Einstein lecture at Brown University on the topic of String Theory and Intelligent Design. He is widely considered to be the leading candidate for next year’s Templeton Prize. Cleaver, a prominent string theorist who was a student of John Schwarz (the co-discoverer of superstring theory) at Caltech, has published more than 40 important research articles on string theory. Like Susskind, his recent interests have been in the area of string cosmology.
Next year the institute will open its doors with a year-long program on the topic of the multiverse, led by theoretical cosmologist George F. R. Ellis visiting from the University of Cape Town. Ellis, the 2004 Templeton Prize winner, explains that the traditional view of an opposition between faith and science has been made obsolete by the latest research in string theory and cosmology. Says Ellis, “In the end, belief in a multiverse will always be just that — a matter of belief, based in faith that logical arguments proposed give the correct answer in a situation where direct observational proof is unattainable and the supposed underlying physics is untestable.”
The new institute will be named the Stanford Templeton Research Institute for Nature, God and Science (STRINGS) and will collaborate with other related Bay Area organizations, including Stanford’s own KIPAC (Kavli Institute for Particle Astrophysics and Cosmology) and Berkeley’s CTNS (Center for Theology and the Natural Sciences). Steve Kahn, the director of KIPAC, welcomed the formation of the new institute saying “We’re very pleased to have such a major institution on campus led by two such prominent physicists working on cosmology. In this era of declining NSF and DOE budgets, we need to branch out from traditional approaches to science. We expect to collaborate with the new institute to help us seek funding from sources such as the President’s FBCI initiative.” Besides the physicists, several faculty from other Stanford departments will be affiliated with the Templeton institute, including computer scientist Donald Knuth, author of the recent book Things a Computer Scientist Rarely Talks About.
According to Dr. John M. Templeton, Jr., president of the Templeton foundation, “the idea for the institute grew out of our involvement with a series of lectures at Stanford in the area of biology. At those lectures the biologists pointed out to us that it was the physicists on campus who were doing work most closely related to our foundation’s interests, something we had already noticed through our Cosmology and Fine-tuning Research Program. As the latest cutting-edge research in physics has caused physicists to rethink what it means for a theory to explain experimental data, the wedge driven by Galileo between science and religion has begun to close. We’re very proud to be able to support and encourage this trend.”
Encouragement also comes from some other members of the Stanford physics department. Nobel-prize winning theoretical physicist Robert McLaughlin was quoted as saying “theoretical particle physics is just getting old and losing its youthful good looks. Even Ed Witten has given up on it. This latest plan for the cosmology/multiverse/string theory crowd to join up with Templeton reminds me of a woman deciding to become a nun when she gets too old to attract men. But if it gets them out of the physics department, I’m in favor of it. Don’t let the door hit you on the way out, guys.”
The Perimeter Institute in Canada is known as a center for research in Loop Quantum Gravity. This week they have come up with an extremely clever way to make string theorists look bad. They’ve scheduled a week of talks on String Phenomenology, ending this Friday on April Fool’s day. Most of the talks are related in one way or another to the “Landscape”, with talks by Kachru on “Landscape Architecture” and DeWolfe on “More Landscape Architecture”. If you’re in the mood for a giggle, tune into these talks tomorrow: it will be all landscape, all the time, from Michael Douglas in the morning to a panel discussion in the evening moderated by Herman Verlinde on the topic “Landscape: What Is It Good For?”. It’s quite possible the panel discussion will be very short.
John Baez has just put out a new issue of his This Week’s Finds in Mathematical Physics, dealing partly in more detail with the material about Clifford modules mentioned here a couple weeks ago. I’ve added as the first comment here something he had some trouble submitting as a comment to the older posting on this topic.
John briefly mentions a relation of all this to Bott periodicity in topology, using a very abstract homotopy construction involving spectra. A more concrete version of this can be found in Milnor’s book on Morse theory. For the relation of Clifford algebras and K-theory, the standard refererence is the 1964 paper “Clifford Modules” by Atiyah, Bott and Shapiro published in the journal “Topology”. The crucial fact they describe is how the Thom isomorphism in K-theory (which is essentially the same fact as Bott periodicity) is related to the structure of Clifford modules. Greg Landweber has recently worked out an interesting equivariant version of this story.
Greg also has a nice new paper with Megumi Harada about the K-theory of a symplectic quotient, that looks like it should imminently appear on the arXiv.
John also mentions some recent work of Dror Bar-Natan, Thang Le and Dylan Thurston on the Duflo isomorphism. This is a beautiful story, and also has a relation to Clifford algebras that John doesn’t mention. For this, see Eckhard Meinrenken’s talk at the 2002 ICM in Beijing.
Last week the 2005 International Linear Collider Workshop was held at SLAC, and the talks are available on-line. At the conference it was announced that Barry Barish of Caltech would lead the Global Design Effort for the International Linear Collider. The hope is to finish a design for the ILC in 2007, have a site chosen in 2008 and construction done by 2015, allowing the ILC to run at the same time as the LHC for several years, with each machine providing data that could help decide how best to use the other one.
This schedule seems overly optimistic to me. Because of the huge US deficits, getting the kinds of increases in the DOE budget needed to build the ILC in the US looks quite difficult, and, even if this were possible, funding constraints would probably stretch out the construction schedule. In Europe, CERN is devoting all its resources for a while to the LHC, and is backing an alternate, more speculative linear collider technology called CLIC. The most likely course of events seems to be that people will be waiting to see what the LHC finds and how the CLIC technology works out before fully committing to a new linear collider. If so, a decision about what to build and where to build it would probably not take place until almost 2010, with another decade probably required to actually construct the machine.
At the SLAC conference, the main theoretical talk was one by Savas Dimopoulos on New Models about his work with Arkani-Hamed on split supersymmetry and models where both the cosmological constant and the weak scale are anthropically determined aspects of the “Landscape”. There increasingly seems to be a disconnect between the experimentalists planning experiments at the LHC and ILC, whose plans often revolve around the search for low-energy supersymmetry, and the string theory inspired theorists, who are spending their time wandering around the landscape. From the landscape point of view, it seems that low-energy supersymmetry is extremely unlikely.
For more from theorists wandering around the landscape, see the talks at this week’s Workshop on N=1 Compactications at the Fields Institute in Toronto. The talks from this workshop are starting to become available on-line. Next week there will be even more of this at the Fields Institute, as it hosts a Workshop on String Phenomenology.
I spent the last two days up in Cambridge, mainly attending the conference in honor of Sidney Coleman. Sadly, Coleman is in poor health, suffering from Parkinson’s disease, and was unfortunately unable to attend the talks in his honor. They were videotaped so that he could watch them later.
For me as for many particle theorists, taking Coleman’s quantum field theory course at Harvard was one of the great intellectual experiences of my life. Another such experience was reading and learning from his great Erice lectures, both the late seventies ones as they came out, as well as going back to his earlier ones that started in 1966. These were collected in 1985 in the book “Aspects of Symmetry”, allowing me and many others to replace a stack of dog-eared Xeroxes with a more durable volume. The fact that Coleman stopped giving these lectures after 1979 was to me one of the first indications that particle theory was entering a much less promising phase of its history. Coleman never really warmed to the topics of supersymmetry and string theory.
For much of his career Coleman played the role of guru for the particle theory community, generously sharing his unmatched insights into quantum field theory. He would sleep through the morning (famously announcing that he couldn’t teach a 9am class because he couldn’t stay up that late), get into his office late in the afternoon, then spend hours dealing with a long line of people waiting to talk to him to try and get some help with whatever problem they were working on. Steven Weinberg spoke for many people at the conference when he said that Coleman was the single person he had learned the most physics from.
The conference was extremely well-attended, with the large lecture hall in the physics building at Harvard overflowing on Saturday. I don’t think I’ve ever seen so many Nobel prize winning particle theorists in one place. They included Gell-Mann, Glashow, Weinberg, ‘t Hooft, Gross, Wilczek, Wilson, as well as Fields medalist Edward Witten. One of the few living Nobel particle theorists who couldn’t make it was David Politzer, who very much directly owes his prize to Coleman.
I won’t describe the talks in detail, this has been done pretty accurately already by Lubos Motl (who I got to meet in person for the first time). Physics weblogging was very well represented at the conference: besides Lubos, Jacques Distler was liveblogging from one corner of Science Center B on Friday, and Serkan Cabi was also there. Sean Carroll also has some comments about Coleman.
Among the more historical talks, perhaps the most interesting was that of Gerard ‘t Hooft (Lubos seems to have missed ‘t Hooft’s comment that he shouldn’t be referred to as “Gerardus”, a formal version of his name that appears on his Nobel citation and his passport, but is otherwise not much used). ‘t Hooft gave his version of the asymptotic freedom story. He said that he had computed the Yang-Mills beta function a couple years before Gross-Wilczek-Politzer, but didn’t realize that this result wasn’t known to the experts. He pointed out that everyone else had experience only in computing the scaling behavior of non-asymptotically free theories, whereas the first theory he did the computation for was an asymptotically free one, so he thought this was unremarkable. He did say that Gross-Wilczek-Politzer deserved the Nobel since (besides being the ones to publish the beta-function result) they had understood how to use this to explain Bjorken scaling, something that he hadn’t known about. He said his advisor Martin Veltman had told him that the Yang-Mills scaling behavior wasn’t relevant to experiment since experimentalists only cared about what happens on mass-shell. Luckily Veltman was one of the few Nobel theorists not in attendance, since he would likely have blown a gasket if he had been there to hear some of the things ‘t Hooft had to say about him. ‘t Hooft went on to say that he had learned one important thing from this episode: always immediately publish any new result you have.
There was significant mention of string theory in only two talks, those of Gross and Witten. Gross gave essentially the same talk he gave last October at the 25th anniversary of the KITP. He joked that he had managed to time the award of the Nobel with the KITP celebration by every year for the last thirty years writing to the Nobel Committee and asking them to wait a while before awarding him the prize, something they had been happy to do. At the point of his talk when he said that the question “What is String Theory” was one of the big questions for the future, he stopped to defensively note that since we don’t know what string theory is, it is an idea that can’t be killed, no matter how much certain members of the audience wanted to do this. He went on to claim that since AdS/CFT kind of connects string theory with QCD, string theory is in some sense part of the standard model, so it’s importance is secure. This argument seemed to me pretty disingenuous, since presumably he’s well aware that the problem most critics have with string theory is not with the idea of using it as a dual representation of QCD, but with the idea of getting a TOE out of it, a project which some have called a “colossal failure”. He didn’t have anything to say either about this failure or about the whole Landscape mania.
The last talk was Witten’s, entitled “Emergent Phenomena in Condensed Matter and Particle Physics”. He started by saying that he was afraid the title of his talk might be more exciting than the talk itself. By “emergent phenomena” he meant roughly non-perturbative phenomena in QFT, where the long distance degrees of freedom one observes are not directly related to the local degrees of freedom. He gave QED as an example of a non-emergent theory, QCD an emergent one, with the nature of the electroweak theory still up in the air until we know more about the origin of electroweak symmetry breaking.
He went on to say that gravity messes up this distinction between local and emergent phenomena, since one doesn’t have diffeomorphism invariant local observables. He then quoted his 1980 work with Weinberg (and with help from Coleman) to the effect that you can’t get a massless spin two bound state in a theory with a local stress-energy tensor, saying that this showed that you can’t start with a local theory in Minkowksi space and generate Einstein gravity as an emergent phenomenon. For him the lesson is that if you want gravity as an emergent phenomenon, you need to find a way to first get space-time as an emergent phenomenon, and he believes that whatever the primoridial M-theory underlying string theory is, it should do this. While such a theory doesn’t now exist, he went on to give the AdS/CFT correspondence as the kind of thing he had in mind. There the Weinberg-Witten argument is evaded since a QFT in 4 dimensions is related to a gravity theory in a different number of dimensions (5).
It’s now been exactly one year since I first set up this weblog. At the time I thought the number of those sharing my interests would be very small and hardly anyone would be looking at whatever I put up here. Things have turned out very differently, with an ever increasing number of connections. I started gathering statistics in May of last year. Here’s the average number of connections to the main page per day (there’s a similar number of connections to other pages, from Google searches and links from elsewhere).
May 2004 146
June 2004 240
July 2004 281
August 2004 336
September 2004 315
October 2004 514
November 2004 514
December 2004 572
January 2004 735
February 2005 955
March 2005 (first half) 1109
I’ve enjoyed and learned a lot from many of the comments posted here (at last count there have been 2728, concerning 168 different postings), but a recurring problem has been that many people would like to turn the comment section into a discussion forum for their own personal speculative ideas about physics. This threatens to completely overwhelm discussion of the topics I’m actually posting about. This morning I had to delete several several such comments from different people. Please do not post comments here of this kind. Get your own weblog and do it there. If every so often you want to post a link here to something you’ve written of this kind elsewhere, that’s fine.
It’s been quite a year, especially as the story of string theory just gets weirder and weirder. I have no idea what will happen during the next year, but I’m looking forward to finding out.
