What the M Stands For

Posted on January 3, 2011 by woit

There’s an explanation at the latest Abstruse Goose.

To recycle some of my own writing, from page 107 of NEW, the book:

When I was a graduate student at Princeton, one day I was leaving the library perhaps thirty feet or so behind Witten. The library was underneath a large plaza separating the mathematics and physics buildings, and he went up the stairs to the plaza ahead of me, disappearing from view. When I reached the plaza he was nowhere to be seen, and it is quite a bit more than thirty feet to the nearest building entrance. While presumably he was just moving a lot faster than me, it crossed my mind at the time that a consistent explanation for everything was that Witten was an extra-terrestrial being from a superior race who, since he thought no one was watching, had teleported back to his office.

And, before anyone takes this seriously, I certainly don’t believe this is the explanation for the “M” or that any actual teleportation occurred. To quote the next paragraph of the book:

More seriously, Witten’s accomplishments are very much a product of the combination of a huge talent and a lot of hard work. His papers are uniformly models of clarity and of deep thinking about a problem, of a sort that very few people can match. Anyone who has taken the time to try and understand even a fraction of his work finds it a humbling experience to see just how much he has been able to achieve.

Update: Clifford Johnson at Asymptotia points out a recent talk by Witten to a non-specialist audience about knots. It there is a Martian plot going on here, at least it has led to some wonderful insights about mathematics and quantum field theory that human beings might never have otherwise been able to figure out…

Posted in Uncategorized | 13 Comments

Ancient History

Posted on December 31, 2010 by woit

Sometime around now is the tenth anniversary of my first foray into the business of public criticism of string theory. I wrote something up over the end-of-year holiday in 2000, and circulated it by e-mail to a list of prominent theorists (some of whom I knew, some I didn’t), asking for advice. The main motivation was that it seemed to me that it had become clear that string theory had failed as an idea about unification and while this was increasingly well understood in the particle theory community, the news had not gotten out to the wider world. Instead, a fairly active campaign to promote string theory to the public continued unabated. This was a rather peculiar situation, one that I felt someone should do something about, and I was curious what my correspondents thought of it. Most responded with quite interesting comments on their views on the matter, and one of them put me in touch with an editor at Physics Today. After some back and forth with Physics Today it became clear that they were unlikely to publish anything on the matter, especially from me, so in February I posted what I had written to the arXiv as String Theory: An Evaluation.

Hard as it is to imagine, back in those days there were no physics blogs. Perhaps the closest thing was Usenet newsgroups, especially sci.physics.research, where John Baez and others had taken on the thankless job of moderating discussions which often addressed issues about string theory. The archive of these discussions is here, and some discussion of my arXiv piece broke out there, appropriately in a thread about Lie algebra cohomology. For my first posting joining that discussion, see here. This led to my first encounters with the surprising phenomena of Jacques Distler and Lubos Motl.

Scientifically, not much has changed in ten years, but the public perception of string theory has changed a lot and become much more realistic. The next decade will undoubtedly be dominated by the effects of whatever we learn over the next few years at the LHC, although I don’t think this is likely to affect proponents of string theory unification very much. Many of the remaining defenders of this idea are by now pretty well dug in and make it clear that “never give up” is their policy, even if it involves abandoning all hope of understanding this universe and putting faith in the existence of others.

One outcome of this that I never expected ten years ago is that I now have a book that has been published in Czech, with the title Dokonce ani ne spatne. I can’t read a word of it, which doesn’t matter except that I’m intrigued to see that Martin Schnabl has written an afterword and wonder what he has to say. The publisher just sent me a few copies, but I can’t think of anyone I know who reads Czech to give them to. Other than Lubos, of course, but I suspect he wouldn’t appreciate the gesture…

Posted in Not Even Wrong: The Book | 50 Comments

Short Items

Posted on December 21, 2010 by woit
  • The Tevatron last week passed the milestone of 10 inverse femtobarns of luminosity delivered to the experiments. That’s about 1.5 quadrillion collisions.
  • Presentations from the Simons Center Inaugural Conference, discussed here, are now on-line.
  • Luis Alvarez-Gaume and John Ellis discuss here the Higgs mechanism, its history and the question of who should get a Nobel prize if the Higgs particle is found There’s the usual attempt to cut Anderson out of the picture (for more see here), I gather this is payback for his opposition to the SSC.
    [Note added: the “payback for his opposition to the SSC” remark was a very lame attempt at snarky humor. There’s no reason to believe these authors had such a motivation. For one thing, while US particle physicists are often quite bitter about Anderson and the SSC, those who work at CERN like Alvarez-Gaume and Ellis are much less likely to feel this way.]
  • The Cambridge City Council has passed a resolution congratulating Yau and Nadis on the publication of their book about Calabi-Yaus, The Shape of Inner Space.
  • Barry Mazur and William Stein are working on a book entitled What is Riemann’s Hypothesis?, with a rough draft available here.
  • If you want to seriously learn algebraic geometry, maybe the best way would be to take Ravi Vakil’s Math 216 course on-line here. OK, I should have told you about this at the beginning of the semester, because if you start now you’ll be way behind. But, since it’s on-line, maybe that doesn’t matter. You could try and catch up…
  • There have been various recent claims to see evidence of pre-big bang physics in the CMB (see here and here), although the significance level of these results seems to be about that of the discovery of Stephen Hawking’s initials in the same data. Several preprints have already appeared criticizing the first of these claims, Sabine Hossenfelder deals with the second here. John Horgan blogs about this as “science faction” here, and discusses it with George Johnson here.
  • Mike Duff seems to now be deep in Lubosian territory, publishing a letter to New Scientist that accuses those who don’t accept the supposed “academic consensus of superstrings and M-theory” as being just like the crackpots and anti-Semites who refused to accept Einstein’s relativity back in the 20s. According to Duff, the explanation for criticism of string/M-theory is that:

    when people don’t like what science tells them, they resort to conspiracy theories, mud-slinging and plausible pseudoscience.

    • Update: The America COMPETES Reauthorization has just passed the House and will go to the president to be signed, something no one expected to happen a week or so ago, more details about the legislation here. I gather that it authorizes 5 to 7% increases for science agencies. Problem is that these are not the actual appropriations, which are still up in the air, awaiting action next year by the next Congress. But this does indicate that there is bipartisan willingness to at least pay lip service to protecting the research and development part of the budget.

    Posted in Uncategorized | 18 Comments

    HEP News

    Posted on December 17, 2010 by woit

    Besides the dramatic new CMS results mentioned in the last two postings, there’s other news from the high-energy frontier as it moves from Illinois to Geneva.

    Earlier this week the MCTP hosted a workshop on LHC First Data. Today at CERN was the LHC end-of-year jamboree, talks available here.

    Plans for next year’s LHC run were made at Evian last week and will be finalized at Chamonix next month. Beam re-commissioning will start February 21, and it looks like the goal will be to run the machine at 4 TeV/beam (up from 3.5 this year) and accumulate a total luminosity of 1-3 inverse femtobarns. Instead of shutting down during 2012 to fix magnet interconnections, the plan now is for the LHC to continue running through 2012, accumulating enough data to definitively see or rule out a Standard Model Higgs and finally put the Tevatron out of business.

    Today at Fermilab people are looking backwards, with a symposium celebrating the 25th anniversary of first collisions at the Tevatron. While a proposal has been put forth to keep the machine running through FY 2014, the budgetary situation looks increasingly likely to put them out of business, no matter what CERN does. The dysfunctional nature of the US federal budget process means that the laboratory is already several months into FY 2011, with no budget, operating under a “continuing resolution” that allows them to spend money at the same rate as last year. Last night, an effort to pass an “omnibus” spending bill for the rest of FY 2011 allocating total spending at the same level of FY2010 was defeated. This means that until February and the next Congress, Fermilab and the rest of the government will operate without a budget. At some point after that, the Republicans plan to try and pass a budget cutting spending from the FY2010 level. Fermilab could very well find itself this Spring finally finding out that its FY2011 budget has been cut, with only a few months left to get spending down to the appropriated level. Budgetary problems are not just affecting the Tevatron, with plans for an underground laboratory in South Dakota dedicated to neutrino and other experiments now up in the air as the NSF has withdrawn its support for the project.

    President Obama did make an inspiring speech about his dedication to support Research and Development spending.

    Posted in Experimental HEP News | 10 Comments

    String Theory Fails Another Test, the “Supertest”

    Posted on December 17, 2010 by woit

    Wednesday’s CMS result finding no black holes in early LHC data has led to internet headlines such as String Theory Fails First Major Experimental Test (for what this really means, see here). At a talk today at CERN, yet another impressive new CMS result was announced, this one causing even more trouble for string theory (if you believe in purported LHC tests of string theory, that is…).

    Back in 1997, Physics Today published an article by Gordon Kane with the title String Theory is Testable, Even Supertestable. It included as Figure 2 a detailed spectrum which was supposed to show the sort of thing that string theory predicts. Tevatron results have already caused trouble for many of these mass predictions. For example, gluinos are supposed to have a mass of 250 GeV, but the PDG lists a lower bound (under various assumptions) of 308 GeV. At CERN today, the CMS talk in the end-of-year LHC jamboree has a slide labeled “First SUSY Result at the LHC!”, showing dramatically larger exclusion ranges for possible squark and gluino masses. Over much of the relevant range, gluino masses are now excluded all the way up to 650 GeV. It looks like string theory has failed the “supertest”.

    If you believe that string theory “predicts” low-energy supersymmetry, this is a serious failure. Completely independently of string theory, it’s a discouraging result for low-energy supersymmetry in general. The LHC has just dashed hopes that, at least for strongly-interacting particles, supersymmetry would show up just beyond the energy range accessible at the Tevatron.

    Posted in Experimental HEP News | 35 Comments

    Physicists Finally Find a Way to Test Superstring Theory

    Posted on December 15, 2010 by woit

    More than ten years ago, the New York Times ran a story explaining that Physicists Finally Find a Way to Test Superstring Theory. At the time, the test was scheduled to start in 2005-6:

    In fact, it might be possible to concentrate so many heavy gravitons into a tiny volume of space that they would collapse in on themselves and create miniature black holes, those cosmic sinkholes from which nothing can escape. Experiments like this will be on the agenda when the Large Hadron Collider begins operation in five or six years at the CERN accelerator center in Geneva. ”These black holes should be quite safe,” Dr. Giddings said, for they would rapidly evaporate.

    Today CMS released the results of the long awaited test of superstring theory, based on 35 inverse picobarns of data. It failed.

    Update: Since this is getting wider than usual attention via Slashdot, I suppose I should remove tongue from cheek and make clear what is going on here. Claims such as the one in the 2000 Times headline always were nonsense: string theory unification failed long ago because it can’t predict anything. Various physicists back then came up with “string theory inspired” models of extra dimensions that would in principle have observable effects at LHC energies. There never was any reason at all to believe these models (and they were no more “predictions of string theory” than anything else), but there was a lot of hype about them, often promoted to the media by people who should have known better. Now that the LHC is finally working, the result is exactly what everyone expected: these exotic phenomena that had no good reason to happen don’t actually happen. It’s great evidence that the LHC is working as expected, but not an experimental refutation of string theory.

    Posted in Experimental HEP News | 27 Comments

    This Week’s Hype

    Posted on December 11, 2010 by woit

    This week’s contribution to the long tradition of universities issuing press releases hyping non-existent “experimental tests of string theory” by their employees is from Duke University, which advertises “String Theory in a Lab“. This is based on a paper that just appeared in Science describing measurements of the viscosity of a Fermi gas. The paper explains the relationship of the measurements to string theory as:

    The measurement of the viscosity is of particular interest in the context of a recent conjecture, derived using string theory methods, which defines a perfect normal fluid.

    referring to this paper which first suggested that gauge/gravity duality implied a value of 1/4π for the ratio of shear viscosity to entropy density.

    In the press release, this connection to string theory has been promoted to a headline, as well as to the claim that:

    The results may also allow experimental tests of string theory in the future.

    which I suppose is better than the usual claim in these press releases that what is being promoted is already an experimental test of string theory. It seems likely that one reason this isn’t yet an “experimental test” is that the data comes out 4 to 5 times higher than the string theory value.

    Posted in This Week's Hype | 30 Comments

    Math Research Institute, Art, Politics, Transgressive Sex and Geometric Langlands

    Posted on December 4, 2010 by woit

    I learned from a colleague last night about recent events bringing together the topics of the title of this posting, something that one wouldn’t have thought was possible. Last Wednesday there was a showing in Berkeley of Edward Frenkel’s short film Rites of Love and Math, together with the Yukio Mishima film Rites of Love and Death that inspired it. Frenkel is a math professor at Berkeley, and one of the leading figures in geometric Langlands research (which he describes as a “grand unified theory of mathematics”). He’s also a wonderful expositor, almost single-handedly making the beauty of a subject initially renowned for its obscurity accessible to a much wider audience. Recently he has worked with Witten on relations of geometric Langlands to quantum field theory, and with Langlands and Ngo on relations to number theory. At the same time, while a visiting professor in Paris, he co-directed (with Reine Graves) and acted in this new film.

    MSRI was one of the two sponsors of the showing of the film, but pulled out of this role recently, for reasons explained here by MSRI director Robert Bryant. He had found that some people in the math community were upset by the film and MSRI’s involvement with it, feeling that it glamorized an objectionable view of the relationship of women to mathematics. There’s a plan to organize some sort of event at MSRI to discuss the issues brought up by the film and the decision to withdraw sponsorship.

    I still haven’t seen the film, although I gather that a DVD will soon be available. Congratulations to all involved in this for finding a unique way to make mathematics and mathematicians look interesting and worthy of media coverage. I had no idea it was still possible to stir up controversy in the Bay area with art involving transgressive sex, and would never have thought that using research mathematics was the way to do it.

    Update: Andrew Ranicki has written a review of the film for the London Math Society newsletter, available here. He identifies the notorious equation in question (5.7 of http://arxiv.org/abs/hep-th/0610149), and makes the comment that, sartorially, this film is a breakthrough, since, in other films:

    By and large, male mathematicians are portrayed as crazies who are smart and lovable, but badly dressed. Likewise for female mathematicians, although they tend to be better dressed. This said, in the film under review, the actors are either very well dressed, or not dressed at all.

    Posted in Uncategorized | 25 Comments

    The BMO Financial Group Isaac Newton Chair in Theoretical Physics

    Posted on November 29, 2010 by woit

    I learned this morning from Matin Durrani’s blog that the Perimeter Institute has announced today the first of what they expect to be five very well-funded Perimeter Research Chairs in theoretical physics. The next four will be named after Maxwell, Bohr, Einstein and Dirac (as well as whatever other wealthy individual or organization comes up with funding).

    The BMO Financial Group is putting up $4 million and $4 million is coming out of the Perimeter endowment (which is mostly from Blackberry’s Mike Lazaridis). An endowment of $8 million for a chair is quite high. It seems that typical numbers for endowment payouts these days are around 5%, so this would make available $400,000 or so a year to pay some prominent theorist. For comparison, the Simons Foundation has recently announced that it will fund endowed Math+X chairs aimed at mathematicians working at the interface with some other subject. Simons may be the wealthiest hedge-fund manager in the world, but he’s a piker compared to the Canadian financiers, with only $1.5 million going to each chair (to be matched by $1.5 million from the institution that gets the chair, for a total of $3 million). Then again, it just may be that prominent mathematicians are dirt-cheap compared to prominent theoretical physicists.

    The Perimeter Institute in recent years has moved away from supporting non-mainstream topics in theoretical physics, while expanding dramatically. The only two conferences announced there for the next year or so are on the topics of LHC physics and AdS/CFT, about as mainstream as one can possibly imagine. If they manage to fund what might be the five highest-paid theoretical physics positions in the world and hire the people they want into them, they will be well on their way to a dominant position in the subject. While, like most industries these days, the tactic here is to shower the top few people in the field with cash, they are also expanding their hiring at more junior levels. According to the rumor mill, last year out of a total of fourteen people hired to tenure-track positions in theoretical particle physics in North America, three of the fourteen went to Perimeter.

    For more on this, see here, and an interview with Lazarides and the BMO CEO here.

    Posted in Uncategorized | 15 Comments

    Assorted News

    Posted on November 18, 2010 by woit
  • HEPAP is meeting in Washington today, presentations available here. The idea of this regular meeting is for the US HEP community and the funding agencies to meet and plan for the future, something that’s not easily done in an environment where these agencies have no budget at all for the current year, just an authorization to spend money at last year’s rate that expires in a couple weeks from now. No one seems to be sure what funding prospects are for the next few months, much less the next few years. Fermilab is dealing with this situation by offering 600 of its staff incentives to quit or retire next month (see here). There’s a new DOE Committee of Visitors report out here, it contains the bizarrely familiar recommendation of all such reports: the US needs to fund more HEP theory students (they don’t explain why, or where the money should come from).
  • In dark matter news, Princeton this week hosted a workshop on the subject, talks available here. Still no results from the latest Xenon100 run. This week’s Nature has a nice review of the various searches for WIMP dark matter, with conclusion:

    With the advent of the Large Hadron Collider at CERN, and a new generation of astroparticle experiments, the moment of truth has come for WIMPs: either we will discover them in the next five to ten years, or we will witness their inevitable decline.

    (Update: a commenter points out that this article is also available on the arXiv here.)

    One new astroparticle experiment that is supposed to look for evidence of dark matter is Sam Ting’s Alpha Magnetic Spectrometer, set to be launched in February, and described in a front-page New York Times article yesterday.

  • Ten days after first collisions, Alice already has two papers out (here and here) with experimental results on lead-lead collisions at an energy more than an order of magnitude higher than ever before. String theorists are very enthusiastic about this (see here and here), claiming that what is being observed is “properties of a type that can be nicely captured using string theory models”. I’d be quite curious to see any AdS/CFT based predictions that could be compared to these new results (or to forthcoming ones).
  • For the latest from the LHC, see here. Current plan is to have a proton-proton beam back around February 21, followed by at least 2 weeks of beam recommissioning. The proton run would end in November, followed by another ion run. First estimates for 2011 are that the run will be at 4 TeV/beam, and a “reasonable” estimate of total luminosity would be 2.2 inverse femtobarns, double the initial goal. Even more optimistically, the possible “ultimate reach” for next year would be a luminosity that would give a total of 7.2 inverse femtobarns if sustained over the hoped for 200 days of running. This kind of higher luminosity would allow the LHC to see evidence of a Higgs over the entire expected range, as well as allowing it to finally overtake the Tevatron in the Higgs race. The experiments so far are reporting results that match exactly the Standard Model, more announcements to come at the Winter Conferences early next year.
  • There’s an interesting trend of our LA-based theorist-blogger-media-stars starting to resist making dubious media appearances. A few months ago Sean Carroll described storming off the set of a TV pilot here. Now Clifford Johnson (whose media mishaps include appearing as a scientific expert on the question of how big women’s breasts need to be to crush beer cans, see here) tells us that Sometimes I Say No.
    • Posted in Experimental HEP News, Uncategorized | 28 Comments