Various and Sundry

Posted on February 6, 2010 by woit
  • Now that the plan for running the LHC over the next few years is in place, one can start to get an idea of what new physics might emerge from it between now and 2013. For the question of the Higgs, Tommaso Dorigo does some analysis here, going back to 1999 Tevatron projections to see how reliable they were. He concludes that the 1999 projections were accurate for the mass range above 135 Gev. Below that, they depended on assuming a silicon detector upgrade that never was funded. His bottom line is that he sees the Tevatron as ultimately able to rule out the Higgs at 95% confidence level over the entire relevant mass range, but unable to come up with convincing evidence of its existence if it is in the lower part of this mass range. For this, the LHC will be required, but this will have to be after the move to higher energy in 2013:

    The LHC experiments will be unable, in my opinion, to make up in two years of data taking, and with the 3.5 times larger energy, for the 8-year advantage in running time of the Tevatron. The Higgs boson will be unlikely to be discovered before 2013, and it will probably be a sole LHC business; however, until then the Tevatron will retain the better results as far as the mass exclusion range is concerned.

  • Operating on a different reality plane is Michio Kaku:

    “We’re beginning to test string theory with the large Hadron collider outside Geneva, Switzerland, costing ten billion euros, the most expensive machine that science ever created. That’s what I do for a living,” said Kaku in a recent conference call interview from New York.

    This is from a story mainly about Kaku’s new TV show on the Discovery Channel, accurately entitled Fact or Fiction? Physicist Dr. Michio Kaku blurs the line between science and science fiction.

  • NPR has recently started up a project called 13:7 Cosmos and Culture. It’s a blog “set at the intersection of science and culture.” Unfortunately, NPR’s conception of the intersection of physics and culture is occupied by Stuart Kauffman, who has a series of posts arguing that the physical universe cannot be described by physical laws (see here and here). In the most recent one, Kauffman takes up the complicated subject of decoherence and the emergence of classical behavior in quantum systems, and claims to have (inspired by Karl Popper) an argument based on special relativity showing that decoherence cannot be described by any fundamental law of physics. This is supposedly experimentally testable:

    As it happens these ideas may have testable consequences, for they should be more marked as the relative velocities of the event A and one or two receding detectors increase toward the speed of light. And, since quantum decoherence is easier if the quantum processes in the “environment” are locally abundant, they should be more visible in that case. These are testable consequences of Popper’s original idea and my use of it with credit.

    I hope the experiments are done.

    For more about all this, Kauffman refers to his article here from the Edge web-site, where he argues that that the brain is “quantum coherent”, and:

    Reversibility of the coherent to decoherent-classical to recoherent quantum states are essential to my hypothesis for I wish the brain to be undergoing such reversible transformations all the time.

    He gets around problems with time-scales by noting that:

    The time scale of neural activities is a million times slower, in the millisecond range. But it takes light on the order of a millisecond to cross the brain, so if there were a dispersed quantum decohering-recohering mind-brain, reaching the millisecond range is probably within grasp of a quantum theory of the mind-brain system.

    I suppose it is true that it might take light a millisecond to cross one’s brain, if one’s brain were about 200 miles across…

  • Normally I don’t think I can ethically post gossip about mathematician’s love lives here, but once it has already appeared in the media…
  • Some ex-colleagues from here at Columbia are among those launching the Journal of Unpublishable Mathematics. From what I hear, they haven’t yet published anything, but have had nominations.
  • Last week the algebraic geometer Eckart Viehweg passed away at the age of 61. His wife Helene Esnault is also an algebraic geometer, and recently posted an article on the arXiv based on joint work, with a heart-breaking abstract.
    • Posted in Uncategorized | 14 Comments

    Particle Theory Job Market

    Posted on January 29, 2010 by woit

    Erich Poppitz has updated his statistics on the high energy theory job market to include data from 2009. He counts hirings to tenure-track faculty jobs, using data from the Theoretical Particle Physics Jobs Rumor Mill. For 2009, out of 12 hires listed on the Rumor Mill, he counts 9 as in high-energy theory, 3 as cosmologists. Of the 9 high energy theorists, he counts 7 as in phenomenology, 2 as in string theory. I’m not sure exactly who he is counting as a string theorist, probably Easson (string cosmology) and either Elvang (now working on QFT amplitudes) or Shih (supersymmetry breaking). It appears that it is now essentially impossible to get a permanent job in a physics department if you’re working on the more formal end of string theory (or string phenomenology, for that matter). You pretty much have to work in cosmology or phenomenology to have some sort of job prospects.

    The academic job market in general in the US is in a terrible state, and this is reflected in the change from an average of around 20 hires per year in recent years to 9 in 2009. It looks like the situation won’t be any better for 2010. The imbalance between the large number of new PhDs and postdocs, and very few permanent jobs is quite remarkable. According to the postdoc rumor mill, this year already 8 people have accepted postdocs in Princeton, at the university and the IAS, making this small segment of the community large enough to fill almost all the available permanent jobs.

    The US economy remains on its knees due to the economic crisis triggered by the blow-up of debt instruments, especially those designed by quants often coming from a physics background. Luckily for physics PhDs who now have no hope for a job in academia, what I hear from my financial industry friends is that, unlike the rest of the economy, their companies are doing quite well, embarking on new rounds of hiring.

    Posted in Uncategorized | 43 Comments

    LHC Update, More

    Posted on January 29, 2010 by woit

    According to John Conway, the decision coming out of Chamonix is to go with the first of the two scenarios described here: stay at 3.5 TeV/beam, then a long shutdown to fix all the splices. The idea is to run at 3.5 TeV during 2010 and 2011, stopping for shutdown either when 1 fb-1 has been accumulated, or end of 2011, whichever comes first. The LHC will thus be off throughout 2012, coming back in 2013 for a run at or near the design energy of 7 TeV/beam.

    With the Tevatron counting on having around 12 fb-1 of data at 1 TeV/beam by October 2011, it should remain competitive with the LHC for many sorts of searches, including the search for the Higgs, for much longer than expected. This should be true for more than 3 years from now, until after the LHC has accumulated a significant amount of data at full energy in 2013. The current planning is for Tevatron operation only through FY2011, I wonder whether this will change…

    Update: Science has a story from Adrian Cho here. The D0 co-spokesperson says the decision on running the Tevatron in 2012 “won’t have to be made for several months.” CERN experimenters are quoted as saying that they will still be searching for supersymmetry and extra dimensions. I haven’t seen any studies of exactly what 1 fb-1 at 7 TeV will make possible in terms of doing better than Tevatron limits on such processes and on the Higgs.

    Posted in Experimental HEP News | 5 Comments

    Are There Cosmic Microwave Anomalies?

    Posted on January 28, 2010 by woit

    No.

    The WMAP team has just released a new set of papers based upon seven years of data from their experiment. For a summary of how this new data has sharpened some of their previous results, see the Cosmological Interpretation paper. They have also gone over claims by many groups to have found deviations from the standard cosmological model in their earlier data sets (for example claims to have found “the unmistakable imprint of another universe” which “points to string theory being on the right track.”) In a paper entitled Are There Cosmic Microwave Background Anomalies, the WMAP team reports:

    In most cases we find that claimed anomalies depend on posterior selection of some aspect or subset of the data… We examine several potential or previously claimed anomalies in the sky maps and power spectra, including cold spots, low quadrupole power, quadropole-octupole alignment, hemispherical or dipole power asymmetry, and quadrupole power asymmetry. We conclude that there is no compelling evidence for deviations from the LCDM model

    They give a humorous example of the problem that plagues typical claims to have found such anomalies, showing that the CMB sky map clearly contains the initials of Stephen Hawking, “aligned neatly along a line of fixed Galactic latitude.”

    Update: For the WMAP team’s summary of its new results for the public, see here.

    Posted in Uncategorized | 13 Comments

    LHC Update

    Posted on January 27, 2010 by woit

    Those responsible for the LHC machine are having their yearly meeting this week in Chamonix to discuss the state of the project and plans for the future. Last week a subgroup met to discuss plans for beam commissioning to 3.5 TeV/beam, starting next month. The current schedule envisages beam commissioning to restart around February 19, and best estimate is that it will take about a month to establish safe, stable 3.5 TeV beams and begin extended runs for physics purposes. There’s a plan for a big media event when first collisions are achieved at 3.5 TeV/beam, something that may require discouraging experiments from announcing observation of high-energy collisions that happen before the planned moment (evidently this is what occurred last year, when Atlas saw 1.18 TeV/beam collisions before they were supposed to…).

    This year’s schedule includes a possible one-month stop mid-year to increase the beam energy from 3.5 to 5 TeV, but based on the discussions at Chamonix, this looks very unlikely. The most serious problem with the LHC remains the bad splices which are known to exist in the machine, as well as sectors where definitive measurements of all the splices have not been possible (they would require warming up the sector, causing delays of months). The current knowledge of the splices leaves no room for error, even at 3.5 TeV, and going to 5 TeV would require warming up parts of the machine, something which cannot be done during a 1-month stop.

    Discussions are beginning about how long a stop for repairs should be planned for after this year’s run ends in November. To be able to run at 5 TeV/beam will probably require keeping the machine off until May 2011 to fix splices. Going to the design energy of 7 TeV may require even more extensive work on the splices, work that could keep the machine off for all of 2011, with startup again in 2012. To get above 5 TeV, work also needs to be done on retraining the magnets through repeated quenches. Not much of this would be needed to get to 6.5 TeV/beam, but to go all the way to 7 TeV, problems that are still not understood with magnets from one manufacturer will have to be addressed.

    Update: From the Chamonix summary talk, there are two main scenarios now being considered. In the first, the energy of the machine would stay at 3.5 TeV/beam this year and next, with .1-.5 fb-1 integrated luminosity in 2010, 1 fb-1 in 2011, then a year-long shutdown in 2012 to fix all splices before moving to 6.5-7 TeV/beam. In the second, splices would be fixed in stages, running for only 5 months in 2011, at 5 TeV/beam, 1 fb-1 integrated luminosity.

    There will be a summary session at CERN next Friday.

    Posted in Experimental HEP News | 13 Comments

    Physics of the Universe Summit

    Posted on January 26, 2010 by woit

    The New York Times today reports on a Physics of the Universe Summit held a week or so ago in LA. According to the Times, participants stayed at “a Hollywood hotel known long ago as the ‘Riot Hyatt,’ for the antics of rock stars who stayed there.” Talks were a couple miles south at the SpaceX factory, Larry Page of Google was there “handing out new Google phones to his friends”, the magician David Blaine performed card tricks, and Bob Dylan’s son Jesse showed some sort of film about the LHC. The only other information about this that seems to be available on the web is Sean Carroll’s blog posting here, where he gives a link to the slides of his talk.

    Optimist Gordy Kane claimed that the LHC will soon discover supersymmetry, making physics on the verge of seeing “the bottom of the iceberg”. Lisa Randall (who evidently has a new book planned about science and the LHC) argued instead for focusing on less grandiose small problems. She was skeptical about supersymmetry, pointing out that we should have seen various evidence of it by now, and that the “wimp miracle” of a stable superpartner explaining dark matter doesn’t work well “without some additional fiddling with its parameters.” Joe Lykken summarized the situation as:

    We’re confused, and we’re probably going to be confused for a long time.

    Posted in Uncategorized | 9 Comments

    Various and Sundry

    Posted on January 21, 2010 by woit
  • The latest New Scientist has an article about Erik Verlinde’s “entropic gravity”, with enthusiastic remarks from Robbert Dijkgraaf and Stanley Deser. Gerard ‘t Hooft expresses pleasure at seeing a string theorist talking about “real physical concepts like mass and force, not just fancy abstract mathematics”. According to the article, the problem with Einstein’s General Relativity is that its “laws are only mathematical descriptions.” I guess a precise mathematical expression of a theory is somehow undesirable, much better to have a vague description in English about how it’s all due to some mysterious entropy. There’s even an editorial about this:

    Now we could be closing in on an explanation of where gravity comes from: it might be an emergent property of the way objects are organised, much as fluidity arises as a property of water…. This idea might seem exotic now, but to kids of the future it might be as familiar as apples.

    In a new preprint, Lee Smolin uses Verlinde’s work in a very different way, to show that Newton’s law of gravity must emerge from the microscopic quantum gravity approach Smolin favors, that of loop quantum gravity.

  • Also on the New Scientist/entropy front, there’s a review by Craig Callender of Sean Carroll’s new book. I’d been wondering what philosophers of science would have to say about the book, and the reaction to Carroll’s multiverse explanation of the arrow of time was about what I suspected it would be:

    Daring to speculate in the absence of well-confirmed theory, Carroll jumps from clue to clue, from black hole physics to string theory to the holographic principle, until he arrives at his destination: an eternal “mother space-time” from which a multiverse of baby universes are continually bubbling up and pinching off. The mother space-time is a high entropy vacuum that gives birth to universes like our own, some of which we can expect to begin with low entropy. Problem solved, says Carroll, because that is natural.

    Carroll seems slightly embarrassed by the many leaps of faith he asks of his reader in proposing this solution, and the prose of Part IV sometimes reads like the pitch of an honest used-car salesman: “This car is a dream! True, the tyres are bald, brakes unsound and transmission sticky, but you’ll love it!”

    Carroll and other peddlers of multiverses make us an offer: we will explain the unexplained if you add vast unconfirmable matters of fact into your ontology. In this case that includes a host of disconnected baby universes, an eternal mother universe entirely unlike ours, and half a dozen unknown mechanisms to get all this working. Assuming this explains the low entropy past – and with so much unknown it is hard to be sure another conspiracy isn’t lurking within – is this a good deal?

    In most cases I don’t think so. Why is Manchester United perennially a good soccer team? Surely most solutions of the laws of physics don’t have them winning so much. How unnatural (and unfair) those initial conditions are! Nonetheless, a frothy sea of baby universes tempts no one. We shrug and say, that’s just the way it is. Sometimes it is best not to scratch explanatory itches.

  • Witten now has a long preprint out about his beautiful recent work on analytic continuation of Chern-Simons theory that I wrote about here last fall.
  • My colleague Johan de Jong has been working for a few years now on what he calls the Stacks Project, which aims at a detailed, foundational exposition of the theory of algebraic stacks, beginning with the necessary algebraic geometry. He has structured this along the lines of an open source software project, encouraging contributions to the project from other algebraic geometers. The latest addition to the project is a blog.
  • The filmmakers who brought us What the Bleep Do We Know? have recently completed a new film, entitled Ghetto Physics: Will the Real Pimps and Ho’s Please Stand Up!. According to Cornel West “This intelligent and intelligible film is a must-see for all of us.” There may be a theatrical release this year.
  • A huge proportion of the mathematics research literature is now controlled by the publishing company Springer Science + Business Media. Last April there were reports that the owners of the business had it up for sale for about $2.9 billion. The CEO denied these reports, stating “We are not for sale, there is no truth in Springer being sold”. Last month came the announcement that Springer was being sold, to two private equity firms from Sweden and Singapore. The price was about $3.4 billion, with the new owners also taking on $2.9 billion of the company’s debt.

    It’s not clear if there are any implications for mathematics publishing, with this perhaps just a transfer of control of the mathematics literature from one group of private equity firms to another.

  • In the next couple months Princeton University Press will publish a short new popular book on string theory, Steve Gubser’s The Little Book of String Theory. It is only 184 pages long and appears to be somewhat similar to efforts like The Complete Idiot’s Guide to String Theory, String Theory Demystified, and String Theory for Dummies, but less technical, with less graphics, and a lot shorter.

    According to the promotional material, the author

    describes efforts to link string theory to experimental physics and uses analogies that nonscientists can understand. How does Chopin’s Fantasie-Impromptu relate to quantum mechanics? What would it be like to fall into a black hole? Why is dancing a waltz similar to contemplating a string duality?

    and

    After reading this book, you’ll be able to draw your own conclusions about string theory.

    The introduction is available here, and ends with this description of recent debates over string theory:

    I don’t aim to settle any debates about string theory in this book, but I’ll go so far as to say that I think a lot of the disagreement is about points of view. When a noteworthy result comes out of string theory, a proponent of the theory might say, “That was fantastic! But it would be so much better if only we could do thus-and-such.” At the same time, a critic might say, “That was pathetic! if only they had done thus-and-such, i might be impressed.” in the end, the proponents and the critics (at least, the more serious and informed members of each camp) are not that far apart on matters of substance. everyone agrees that there are some deep mysteries in fundamental physics. nearly everyone agrees that string theorists have mounted serious attempts to solve them. And surely it can be agreed that much of string theory’s promise has yet to be delivered upon.

  • For two wonderful but very different short memoirs by mathematicians about aspects of their research work, see William Stein’s Mathematical Software and Me: A Very Personal Recollection, and Michael Harris’s A Mathematical Dream and Its Interpretation.

    • Update: The Onion carries the news that World Physicists Complete Study of Physics. The quote from a physicist is:

    Yeah, that about does it for physics. All done. Math can pretty much take it from here.

    Update: Robert Helling gives his take on the Verlinde paper here. It reminds him of a certain proof that reaches an unreasonable conclusion using the rules “time=money” and “money is the root of evil”. I noticed this via an arXiv trackback. Funny, for some reason there are no trackbacks to my postings on this topic

    Posted in Uncategorized | 17 Comments

    Big Think

    Posted on January 18, 2010 by woit

    A little while ago I did an interview for Big Think, and they just put it up here today, with some editorial comment here.

    I really don’t like watching or listening to myself, so I’m not about to go through the interview and see exactly how what I tried to say came out and later got edited. If I said something unclear or nonsensical, perhaps someone will let me know. Regular readers of this blog are unlikely to hear anything they haven’t read before. Big Think has their own commenting system, and you can comment there if you wish.

    Posted in Uncategorized | 17 Comments

    Particle Theory in Midtown

    Posted on January 17, 2010 by woit

    Particle theory is about to have a significantly higher profile in midtown Manhattan, with the launch of two new programs this spring:

  • The CUNY Graduate Center at 34th St. is starting up an Initiative for the Theoretical Sciences, with a program of colloquia, workshops and public lectures in various areas of theoretical science. In early April there will be a workshop on Emerging problems in particle phenomenology.
  • A few blocks away, at the 27th St. Stony Brook Manhattan campus, the Simons Center for Geometry and Physics will start having seminars February 12 under the title Simons Center Seminars in Manhattan.
    • Posted in Uncategorized | 4 Comments

    Templeton Foundation News

    Posted on January 15, 2010 by woit

    The Simons Foundation isn’t the only one announcing funding opportunities in math and physics. The Templeton Foundation’s list of funding priorities for 2010 is here, with applications opening February 1. In math and physics the topics they want to support research in are:

  • Quantum Physics and the Nature of Reality

    • and

  • Foundational Questions in the Mathematics Sciences

    • At least for 2010, they seem to have lost interest in the Multiverse.

    Templeton is also supporting a member of the Harvard Math Department in a big way, with a grant of $10 million to math professor Martin Nowak to fund a program in Foundational Questions in Evolutionary Biology.

    Posted in Uncategorized | 7 Comments