Quick Links

Posted on June 17, 2011 by woit
  • The House committee responsible for the DOE budget has passed a FY2012 appropriations bill, details here. Total funding for DOE Science is down .9% from FY2011 at $4.8 billion. HEP gets a .2 percent increase, Biological and Environmental Research is whacked %10.6, with the committee opposed to climate and atmospheric research being funded by DOE. The language about DUSEL argues against it becoming a DOE lab, but money is made available to keep options open. There is support for Fermilab’s Project X (the “intensity frontier”), but a warning that it may not be possible to continue funding both the “intensity frontier” and the LHC (the “energy frontier”).

    Fermilab this week announced a program to offer a “voluntary separation program” under which they hope 100 employees will voluntarily leave. They’re clearly trying to better position the lab for tight budgetary conditions ahead.

  • Over in the Czech Republic, Lubos Motl is hanging out with President Vaclav Klaus and is one of the contributors to his 70th birthday Festschrift. Lubos may have a career ahead in Czech politics, too bad he left the US just before the Tea Party movement got going. He would have fit in quite well with them, but I guess at least in the Czech Republic, he can legally become President some day.
  • From Physics World, it seems that Lawrence Krauss will be joining with 13 other very prominent academics to teach at New College for the Humanities, a new private university in London. The new university has caused quite a stir in Britain, since it’s unlike anything else there. Tuition will be set at US private college levels, $29,000/year, twice what other British universities charge. The business plan is not public, but Wikipedia says 10 million pounds in funding for the first two years is coming from private investors, with the 14 senior academics getting a 1/3 equity stake in the venture. It’s unclear how much teaching they’ll each be doing, since most will retain their current positions elsewhere and just give anything from one to 20 lectures per year.
  • The LHC is doing quite well, with over an inverse femtobarn delivered to the experiments already. For the latest, take a look at the slides of the talks here. At the KITP, there was a very interesting talk by Tim Nelson. He addresses the question of whether the LHC detectors, once their searches aimed at standard speculative ideas such as supersymmetry and extra dimensions turn up empty, can be reconfigured to look for other sorts of exotic possibilities, ones that the current triggers are not sensitive to.
  • There’s an article here about filmmaker Errol Morris, whose new film “Tabloid” is coming out later this year. I saw it a few months ago at a showing in New York, and highly recommend it. It’s one of the most surprising and amazing documentaries I’ve ever seen. Real life is much stranger than fiction. In the article, Morris describes his early career, which included having Thomas Kuhn throw an ashtray at him and have him kicked out of the graduate program in philosophy at Princeton. He moved on to Berkeley, where he hung out with Dan Friedan:

    “I felt that he had destroyed my life,” said Morris. It left him reeling for years to come: He still remembers sitting in a coffee shop at Berkeley with Daniel Friedan, a fellow Princeton exile and the son of feminist icon Betty, and commiserating over the frustrating time they’d had out East.

    “I’m talking about all these problems that I had with Kuhn, which was a constant refrain, and he’s telling me about all the problems he’d had in the physics department,” Morris recalls. “He said, you know, ‘They just could not appreciate me. I had discovered a new kind of physics!’ And I thought, ‘Oh, no. This looks bad. This looks very, very, very bad. This is not going to turn out well. We’re both going to the nuthouse.’ ”

    Of course, they didn’t. Friedan would go on to win a Macarthur Fellowship, and be recognized for his pioneering work on string theory. Morris, meanwhile, left academia behind once and for all to make a movie about a pet cemetery, called “Gates of Heaven,” which became a cult classic, and which Roger Ebert described as one of the 10 greatest films ever made.

  • There’s a conference going on this week and next at the ETH in Zurich on quantum gravity, with slides appearing here. My long held belief about quantum gravity is that it’s a problematic subject unless some way can be found to connect it to unification with the rest of physics, and thus some sort of testability or good reason to believe one is on the right track. Matthias Blau promotes string theory by arguing that it should be judged:

    not by, say, its failure to (so far?) provide specific predictions for BSM physics, or disgust with some of the hype and overblown claims regarding string theory (I may share your feelings . . . )

    Among other things, he explains some of the problems with M-theory, then notes that Tom Banks has a highly mystifying recent proposal about this:

    For very recent proposal for how to deal with (some of) these issues, see T. Banks, Fuzzy Geometry via the Spinor Bundle, with Applications to Holographic Space-time and Matrix Theory, arXiv:1106.1179 (and then please explain it to me . . . )

    His talk, together with the recent preprint Is string theory a theory of quantum gravity?, provides a good understanding of what the problems are facing attempts to use string theory to quantize gravity, from the point of view of a string-enthusiast.

    For the latest from the LQG camp, see Carlo Rovelli’s talk here.

    • Posted in Uncategorized | 19 Comments

    This Week’s Hype

    Posted on June 15, 2011 by woit

    Last month’s Quark Matter 2011 conference was a venue for discussion of new results from the first heavy-ion run at LHC energies last fall. I’ve looked a bit at the slides of the talks, but this is an area far from my expertise. One thing I’ve been wondering about is whether the heavily-promoted application of AdS/CFT to studying heavy-ion physics could possibly be tested at the LHC. Does AdS/CFT make any distinctive predictions about how things will change as one goes from RHIC energies to LHC energies, and have these been checked? Looking at the slides, there seem to be all sorts of interesting things being learned about heavy-ion physics, but little mention of AdS/CFT modeling of such phenomena. Perhaps an expert can help by pointing to pre-LHC predictions, and explaining whether they’ve been tested already, or may be in the future.

    Symmetry Breaking magazine today does cover Quark Matter 11, with String theory may hold answers about quark gluon plasma, which appears to mostly contain the same hype about string theory and heavy ion physics that has been current for the last half-dozen years now:

    Now, scientists have begun to see striking similarities between the properties of the early universe and a theory that aims to unite gravity with quantum mechanics, a long-standing goal for physicists.

    Unfortunately there’s nothing in the article about any LHC test of these ideas. The closest we get to that is this from Krishna Rajogopal (his talk is here):

    “String theory is like a gift to us,” Rajagopal said. “We’re challenged with understanding the quark-gluon plasma as a liquid, and while string theory doesn’t give us precision, it can help us get a feel for the shape of the subject.”

    So, I gather that AdS/CFT makes no precise, testable predictions, with the best case to be made for it that “it can help us get a feel for the shape of the subject”, whatever that means. A question for experts: if “String theory may hold answers about quark-gluon plasma”, what are the questions for which string theory is giving answers, and what does the LHC data have to say about these questions?

    Update: David Mateos has posted a write-up of his Quark Matter 2011 talk here. In it, he explains what the problems are with using AdS/CFT to say anything about QCD. In terms of the question of LHC predictions, he gives an example: the dispersion relation of heavy quarkonium mesons moving through the quark-gluon plasma. Unfortunately, this doesn’t look like much of a prediction:

    I emphasize that whether one obtains a visible peak, simply a statistical enhancement or an unobservable effect depends sensitively on many parameters related to the in-medium J/Psi physics. The latter is not sufficiently well understood to make a precise prediction, so all one should take away from figure 3(right) is that there could be an observable effect for some values of the parameters within the acceptable range.

    Posted in This Week's Hype | 41 Comments

    How the Hippies Saved Physics

    Posted on June 13, 2011 by woit

    A review that I wrote of David Kaiser’s How the Hippies Saved Physics is now available at American Scientist. A quick summary is that I think it’s a marvelous book, telling in well-researched and entertaining fashion a story I’ve always wanted to know more about. I’m not convinced though by the main argument of the title, that this group of people “saved physics”, rescuing it from an oppressive “shut up and calculate” ideology by showing the way towards the importance of Bell’s theorem and helping start the field of quantum information theory. Perhaps the author though is just emulating his subjects, known for their playful outlandishness.

    There are quite a few interesting things I learned from the book that didn’t make it into the review. One example is the story of Werner (of EST fame) Erhard’s theoretical physics conferences of the late 70s and early 80s, organized in collaboration with Sydney Coleman and Roman Jackiw. Among the factors that brought these events to an end was the advent of string theory: it was felt that no string theory conference without Witten attending would be taken seriously, and by then Witten wanted nothing to do with EST and its founder (although he had attended, with the likes of Feynman and Weinberg, the earliest conference in the series back in 1977).

    If you find this subject at all interesting, I highly recommend the book.

    For another take on the same subject, from one of its main participants, Jack Sarfatti’s memoir Star Gate is available for free these days in a pre-publication version here.

    I’m afraid that my own description of where the physicists described in Kaiser’s book ended up would not be the field of quantum information theory, but the much larger swamp of dubious claims about quantum physics that is still very influential. For example, this week at the AAAS meeting in San Diego there’s a session on Quantum Retrocausation, see this listing from the World of Parapsychology.

    Update: I should also mention that Chad Orzel discusses the book here and here.

    Posted in Book Reviews | 37 Comments

    $6.5 Million for Entropic Gravity

    Posted on June 12, 2011 by woit

    One of this year’s Spinoza Prizes goes to Erik Verlinde. It comes with 2.5 million euros to fund the prize-winner’s research. Last fall Verlinde received a 2 million euro ERC Advanced Grant to fund his research program, so that’s a total this past year of 4.5 million euros, or about $6.5 million.

    Verlinde’s current research focuses on ideas about “emergent gravity” (see here and here). According to Wikipedia his work explains the observed value of the cosmological constant.

    I’ve no idea how Verlinde will spend the money, but it looks like emergent gravity research will be extremely well financed. $6.5 million I’d estimate corresponds to about 100 postdoc-years. In a couple weeks Verlinde will unveil his latest work at Strings 2011. Since that’s among the most expensive conferences around (see here), perhaps he could chip in to fund it. I’d estimate he should be able to single-handedly fund Strings 20XX through at least 2050.

    Posted in Uncategorized | 19 Comments

    Math and Physics, Summer 2011

    Posted on June 9, 2011 by woit

    This week in Philadelphia the String-Math 2011 conference is going on, planned as the first of a series, with String-Math 2012 next summer in Bonn. Slides of the talks are appearing here. There’s also supposed to be video, but the saved video seems to require some sort of UPenn login, and I’ve not been able to get the streaming video to work. The public talk by Cumrun Vafa puts out the classic message that strings have come to the rescue of physics, unifying QM and gravity, and that:

    Smooth geometry of strings seems to explain all known interactions (at least in principle)

    The techinical talks cover a lot of ground, much of it having little to do with string theory. Michael Douglas’s talk surveys problems related to finding non-perturbative formulations of quantum field theory that one might hope to say something precise about, but it contains a lot more questions than answers. I’m most curious about David Ben-Zvi’s talk tomorrow, so hope that slides or video of that will be available.

    The circle of ideas relating gauge theories, geometric Langlands, TQFTs and representation theory will be getting even more attention than the mathematics of string theory this summer. In a couple weeks will begin a two-part program at Luminy and then Cargese on Double Affine Hecke Algebras, the Langlands Program, Affine Flag Varieties, Conformal Field Theory, Super Yang-Mills Theory. I don’t know who the author is, but some person or group has written up for the occasion a wonderful summary of the current activity in these and related fields of mathematics, see here. Next month, the KITP will be hosting a program on Nonperturbative Effects and Dualities in QFT and Integrable Systems that will cover some of the same topics.

    In some other unrelated news, if you understand French, you can listen to an interesting set of interviews with Pierre Cartier here. Finally, it was announced recently that my colleague Richard Hamilton is sharing this years $1 million Shaw Prize for Mathematics with Demetrios Christodoulou. Congratulations Richard!

    Posted in Langlands | 10 Comments

    New Look

    Posted on June 9, 2011 by woit

    I’ve updated the blog a bit, to a newer, widgetized theme. Functionality should be the same as before. The only issue I’m aware of now is that the “Archives” widget adds an annoying character below its header which I can’t get rid of. This widget may also be the source of problems some people are having (due to some combination of Javascript and incompatibility with latest WordPress version), it may get replaced…

    Please let me know of any other issues.

    Posted in Uncategorized | 13 Comments

    This Week’s Rumor

    Posted on June 8, 2011 by woit

    A couple months ago CDF made the New York Times by releasing results claiming to see a resonance in the invariant mass spectrum of two jets produced together with a W. Last week they released a new analysis with twice as much data, claiming the signal was still there, now at a statistical significance of nearly 5 sigma.

    I recently wrote about this here, explaining the reasons for being skeptical, despite the high statistical significance. One very good reason for being a skeptic is that CDF’s Tommaso Dorigo doesn’t believe this is real, going so far as to put his money where his mouth is, offering a $100 wager to back up his arguments. The crucial question in everyone’s mind has been whether D0, CDF’s competition and sister detector at Fermilab, would see the same thing in its data. If there’s really something there, D0 should see it.

    This Friday there will be a Wine and Cheese talk at Fermilab, where the D0 results will be unveiled, and you can watch this as a live video stream here. But, as one might expect, now that the D0 result is ready to be revealed, people do things like leave print jobs on printers, etc., causing well-sourced rumors to spread. Blogs such as this one seem to be a place where such information tends to end up, so I can report a rumor (based on excellent sources) that Tommaso is right. D0 will report on Friday that there’s nothing there, that they find no evidence for a dijet resonance in the region from 110-170 GeV. They reject the CDF hypothesis of a resonance with a cross section of 4 pb at a significance level of over 4 sigma.

    In other news, the LHC is running very well, with the official goal of this week being to reach an integrated luminosity of 1 fb-1, something that had been the official goal for the entire year (although, unofficially, 2-3 fb-1 is more like it). Right now, they’re around .8 fb-1. This sort of luminosity should finally start to allow in coming months results that either rule out a Higgs in the region it is expected or see first indications if it is there.

    At the KITP, this week marks the start of a program on The First Year of the LHC. Unfortunately for theorists, the only result of data from the first year of the LHC has been to shoot down some of their favorite models, ruling out for instance a large amount of the parameter space where supersymmetry was expected to be found, making the most popular theoretical idea of the last thirty years significantly less popular. The first talk held at the KITP program was this afternoon, and it dealt not with the LHC data, but with the supposed CDF resonance (it appears that news of the D0 result hadn’t yet made it to Santa Barbara).

    Update: The KITP talk is now available here.

    Update: The D0 PRL submission that has been circulating privately for the past few days is supposed to be available at 9am Friday Fermilab time here. See here for other material to be released publicly today.

    Update: Now that the D0 results are officially out, as usual your best bet for informed explanation is to check out what Jester and Tommaso have to say.

    Posted in Experimental HEP News | 34 Comments

    The Quantum Story

    Posted on June 8, 2011 by woit

    Jim Baggott’s The Quantum Story: A History in 40 Moments is now out here and I’ve been starting to see it in bookstores. I read most of it a year or two ago when he sent me a draft of the manuscript asking if I’d take a look at it, and very much enjoyed getting the chance to see it then. If you’re looking for an excellent popular level physics book to read, I highly recommend that you consider this one, which should be accessible to just about anyone, no matter what their background.

    The topic of the book is the story of quantum physics in general, told historically with a structure of 40 vignettes. The first three chapters cover mainly events of the dramatic period of the mid-1920s to early-1930s during which physicists uncovered the basic structures of quantum theory and struggled to make some sense of them. The next two take on the late-40s to mid-70s during which a long succession of discoveries about elementary particle physics drove theoretical progress on quantum field theory and gauge theory, culminating in the Standard Model falling into place in 1973. The material Baggott works with here has been the topic of many other books, but he does a wonderful job of putting it together in a fast-paced but very clear and entertaining narrative. Along the way, the individual stories he tells often contain fascinating details I’d never heard before, even though I thought this was a subject I knew all too well.

    The next to last chapter starts with the 1950s and David Bohm, picking up the thread of later debates and discoveries related to the general problem of the interpretation of quantum mechanics. It brings this story up to date, explaining some of the current questions that are still being debated. The final chapter gives an appropriately short discussion of speculative ideas in quantum gravity and string theory that have dominated theoretical research for the past few decades, making clear that they’re a long ways yet from the solid science that’s the main topic of the book.

    The LHC and the search for the Higgs make up a final epilogue or 41st vignette, accurately describing the high expectations and drama that surrounds the final period of the long wait for new data that is finally coming to an end this year. The story of quantum theory is not a finished one, and we all hope that very soon we’ll get some clues as to where it will go next.

    Posted in Book Reviews | 3 Comments

    This Week’s Hype

    Posted on June 1, 2011 by woit

    The latest New Scientist has a much larger dose of M-theory/multiverse hype than I’ve seen in one place in quite a while. There’s a four-part series on M-theory (here, here, here and here) by Mike Duff. It tells the story of the progress of modern physics over the past century according to the dominant ideology: general relativity, Kaluza-Klein extra dimensions, super-symmetry, superstrings, branes, ending in the apotheosis of M-theory more than fifteen years ago. For the current state of affairs, Duff describes his “M-theory” predictions about the real world (that 4 qubits can be entangled 31 different ways, something discussed here). He ends with the M-theory multiverse and the following comments on whether this can ever be tested:

    So is M-theory the final theory of everything? In common with rival attempts, falsifiable predictions are hard to come by. Some generic features such as supersymmetry or extra dimensions might show up at collider experiments or in astrophysical observations, but the variety of possibilities offered by the multiverse makes precise predictions difficult.

    Are all the laws of nature we observe derivable from fundamental theory? Or are some mere accidents? The jury is still out.

    In my opinion, many of the key issues will remain unresolved for quite some time. Finding a theory of everything is perhaps the most ambitious scientific undertaking in history. No one said it would be easy.

    Here he makes it clear that, at least while he’s still around and enjoying academic prominence because of M-theory, there’s no danger it will face any sort of test it might fail. He answers critics of M-theory by claiming that its failures don’t matter. It’s the dominant paradigm, and will reign as such until someone comes up with a different theory of everything that isn’t a failure.

    Elsewhere in the magazine, there’s a fawning article about the recent Bousso-Susskind paper (see here):

    TWO of the strangest ideas in modern physics – that the cosmos constantly splits into parallel universes in which every conceivable outcome of every event happens, and the notion that our universe is part of a larger multiverse – have been unified into a single theory. This solves a bizarre but fundamental problem in cosmology and has set physics circles buzzing with excitement, as well as some bewilderment.

    No critics of the idea were located by the writer, with the discussion on blogs described as:

    The paper has caused flurry of excitement on physics blogs and in the broader physics community. “It’s a very interesting paper that puts forward a lot of new ideas,” says Don Page, a theoretical physicist at the University of Alberta in Edmonton, Canada. Sean Carroll, a cosmologist at the California Institute of Technology in Pasadena and author of the Cosmic Variance blog, thinks the idea has some merit. “I’ve gone from a confused skeptic to a tentative believer,” he wrote on his blog. “I realized that these ideas fit very well with other ideas I’ve been thinking about myself!”

    Somehow Lubos’s “they’re on crack” take on the subject was missed.

    Finally, the significance of all of this is summarized in an editorial which argues that Bousso-Susskind finally pulls the plug on religion and replaces it with science:

    Cosmologists can now begin to take God seriously, precisely because they can explain him (or her) away.

    Posted in Multiverse Mania, This Week's Hype | 47 Comments

    Quick Links

    Posted on June 1, 2011 by woit
    • The big news of the past couple days has been the release of more data by CDF which continues to show a bump in the invariant mass of two jets produced with a W. Resonaances gives an excellent description of this and its possible significance. Tommaso Dorigo remains a skeptic.

      I can’t do better than the two of them on this story, but here’s my summary take on the situation:

      With the new data, this can no longer be written off as a statistical fluke. 3 sigma you can argue away as such a fluke, but not 5 sigma.

      The main reason to be skeptical though hasn’t been the statistical significance, but the possibility that this is due to bad modeling of the background. The signal is being extracted from a huge background, so a small misunderstanding of the background could be its cause. If this is the case, the new data changes nothing, you expect to continue to see the effect as more data is analyzed.

      The fact that Tommaso is a skeptic carries a lot of weight, since he works on the CDF experiment and understands the problems well. In general, experimentalists want the experiments they work on to make great discoveries, so tend to be optimists about their own results. When someone is skeptical about a result of their own experiment, that should give one pause.

      What would really make the case for new physics here more compelling would be if the result is confirmed by one of the other experiments (DO at Fermilab, CMS or ATLAS at the LHC) that should be able to see the same effect if it is there. These groups have a certain motivation to not just confirm their competition’s discovery (raising the question of why they didn’t find this first), but to convincingly shoot it down. This posting by Pauline Gagnon of ATLAS says that they see nothing in their 2010 data. One expects that D0 is hard at work and should soon release whatever they have found. ATLAS and CMS should also be hard at work looking at the much larger 2011 data samples. We’ll know soon the results, but the public comments of Dorigo and Gagnon don’t sound to me like those they would be making if they knew their experiments had preliminary confidential results confirming the CDF anomaly.

      Finally, while there are lots of theory papers out already with supposed models explaining this, none are really compelling. This is not an experimental result with an obviously attractive theoretical explanation.

    • Abstruse Goose has commentary on SUSY here.
    • In gossip of the mathematics world, it looks like Princeton (the IAS) has stolen away number theorist Richard Taylor from Harvard.
    • Video of Graeme Segal’s Felix Klein lectures this spring at Bonn on quantum field theory are now available, and well worth watching.
    • Other interesting video available is Greg Moore’s lectures on geometry, topology and QFT at Rutgers last fall.
    • For pictures from this years Physics of the Universe Summit, see here. Any info beyond the transparencies caught in the pictures seems to be private.
    • The journal Foundations of Physics will be putting out an issue on “Forty Years of String Theory”. So far articles intended for this have appeared on the arXiv from Dean Rickles, Steven Gubser, and, last night, Steven Giddings. The Giddings contribution is entitled Is string theory a theory of quantum gravity?, and provides an unusually hype-free discussion of the relevance of gauge/gravity duality to hopes to use string theory to understand quantum gravity, writing:

      While string theory addresses some problems of quantum gravity, its ability to resolve these remains unclear. Answers may require new mechanisms and constructs, whether within string theory, or in another framework.

    Posted in Experimental HEP News, Uncategorized | 9 Comments