Not Even Wrong

The New York Times has an article this morning by Dennis Overbye in its Science Times section about the hunt for the Higgs and the various rumors that were circulating earlier this year. It does a good job of accurately summarizing and reviewing the situation (although of course the blogs were and remain the place to go for breaking news, up-to-date and accurate information…). Steven Weinberg recalls the time back in 1977 when he quickly wrote up a paper with Ben Lee about a model concocted to explain rumored “trimuon” events (which turned out not to be there). There are quotes from bloggers Tommaso Dorigo, Gordon Watts and John Conway, and, in a new posting on his blog, Gordon is now trying to deny that he uses the term “Dude” in actual conversation. Unfortunately, anyone at D0 who knows anything seems to have clammed up, no more rumors that I’m aware of about whether they’re seeing anything exciting.

The 2007 Europhysics Conference on High Energy Physics is going on in Manchester, England, and many of the talks are already on-line. This is a conference more aimed at experimentalists than theorists, so there doesn’t seem to be much new in the theory talks. There are so many experimental talks that I think I’ll have to wait for the summary talk to appear to figure out what to pay attention to.

There’s a long list of things I was going to write about, but Sabine and Stefan at Backreaction got there first (here, here and here):

There’s a new chapter out of the particle physics novel The Newtonian Legacy (blogged about here) by Nick Evans. Not often that the Cern Courier carries material about Higgsless models and lingerie in its pages…

There’s a potentially important new paper on the arXiv from Terry Tomboulis, entitled Confinement for all values of the coupling in four-dimensional SU(2) gauge theory. Tomboulis claims to prove that SU(2) lattice gauge theory has confining behavior (area law fall off of Wilson loops at large distances) for all values of the coupling at the scale of the cutoff, no matter how small. This conjectured behavior is something that quite a few people tried to prove during the late seventies and eighties, without success. Tomboulis is one of the few people who has kept seriously working on the problem, and it looks like he may have finally gotten there. The method he is using goes back to work of ‘t Hooft in the late 1970s, and involves considering the ratio of the partition function with an external flux in the center of SU(2) and the partition function with no such flux. For a recent review article about this whole line of thinking by Jeff Greensite, see here. For shorter, less technical articles by Tomboulis about earlier results in the program he has been pursuing, see here, here, and here.

As far as I can tell, even if this holds up, it won’t get Tomboulis the million-dollar Clay prize being offered for the solution of the Yang-Mills Millenium Prize Problem. There the problem is stated as rigorously constructing Yang-Mills for any gauge group, not just SU(2), showing that it has the expected properties, and a mass gap. I don’t know whether Tomboulis’s methods can prove that there is a mass gap. In any case, I also don’t know why the Clay prize asks for a mass gap rather than confinement, which seems more physically relevant.

The latest HEPAP meeting was this past weekend in Washington and presentations are available here. The news from the DOE is that it looks like Congress will approve a FY 2008 HEP budget at or above the White House request of $782.2 million, an increase of at least 4%. This will include $60 million for ILC R and D (up from $42 million in FY2007). This will include funds for site surveys in the US, which in principle will include sites other than Fermilab, although I find it hard to believe a US site other than Fermilab would end up being chosen.

There’s a report from the University Research subpanel that puts near the top of its recommendations “A higher priority in the overall HEP program should be given to funding directed at university-based theoretical particle physics for the purpose of increasing the number of HEP-grant supported graduate students.” Given the continuing high ratio between students getting Ph.Ds in particle theory and jobs for them when they get out, I would have thought the priority would go to finding ways to fund jobs for students once they get out, rather than increasing the number of Ph.Ds.

There’s a recommendation from the P5 panel that the Tevatron should definitely run through FY2009, and in September they’ll start looking at the case for running even longer than that. There’s also a discussion of “European reaction” to comments from the DOE’s Ray Ohrbach that the US needs a plan in case the ILC doesn’t start happening soon. Typical reaction from the Europeans was said to be that the US is not a reliable partner, and makes unilateral decisions without consultation. CERN has recently been promised a budget supplement over the next few years that could pay for an LHC upgrade (they were in hock over the LHC), and by 2016 that would be done and paid for. At that time CERN will have money to spend on a new big project and a higher energy linear collider using CLIC technology would be a possibility (the semi-joke made was that the work advancing this possibility is now going on mainly in the US, at SLAC).

A progress report from the Fermilab Steering Group, which is supposed to report to the Director on Aug. 1, included extensive discussion of “Project X”, a proposal to dramatically increase the power of proton beams by building an 8 GeV proton linac. Part of the idea is that building this smaller linac would help get experience needed for doing the ILC.

Also at Fermilab, I noticed that they have a web-site devoted to the history of the place, and here is a recent talk by Adrienne Kolb on the subject.

According to CNN, one of the “Geniuses who will change your life” is Harvard’s (soon to be Princeton’s) Nima Arkani-Hamed, who is described as follows:

Nima Arkani-Hamed thinks big. He has a theory that our universe is one of an infinite number of universes — meaning the largest thing we can wrap our minds around is actually pretty tiny

He didn’t pull the “multiverse” out of thin air, though. After becoming a Harvard professor at age 30, Arkani-Hamed first made a name for himself by suggesting that our universe is five-dimensional. Then he moved on to the multiverse, theorizing that our own universe has a hidden feature called “split supersymmetry,” which means that half of all particles have partner particles.

The theory will be tested soon in Switzerland’s brand-new Large Hadron Collider (LHC), and if the LHC finds Arkani-Hamed’s partner particles, it could prove that the multiverse is real — and that our place in it is that much smaller.

The claim that if you see split supersymmetry, this proves that the multiverse is real seems pretty much laughable to me.

Clifford Johnson is in Aspen, at what its director describes as a “summer camp for physicists”. He has a posting about his experiences there, describing how the big topic of conversation is the recent Strings 2007 conference. He asks for people to write in telling about which of the Strings 2007 talks they found most interesting (although so far, a half day later, no one seems to have taken him up on this). Like Jacques Distler, after Witten’s talk, Clifford seems to be most impressed by Seiberg’s talk on BMSSM (Beyond the Minimal Supersymmetric Standard Model) physics, based on his recent paper with Dine and Thomas. The idea is that, even with its 105 extra parameters, the MSSM still requires a lot of fine-tuning to get around the LEP bound on the Higgs mass, so you should analyze adding even more terms to the Standard Model besides the minimal supersymmetric ones. Distler was very excited by the Seiberg talk, arguing that these results should have been found years ago but weren’t. Various people wrote into his blog to point out to him that this wasn’t right, that mostly these things had been done a while ago, including by several authors back in 2003 (see hep-ph/0301121 and hep-ph/0310137). Seiberg et. al. issued a revised version of their paper where they added quite a few references, including one to work back in 1999 by Alessandro Strumia (hep-ph/9906266) where he already discussed the impact of the two operators identified by Dine et. al on the Higgs mass.

Update: The debate over string theory really has reached the general public, at least in New York: a few months ago there was a cartoon in the New Yorker, this week, it has made the New York Magazine web-site celebrity coverage.

There’s an interesting exchange today between Sean Carroll and George Johnson on bloggingheads.tv. They cover a range of topics, including the controversy over string theory and the role of blogs. Johnson describes his time last fall at the KITP, telling about drinking very expensive Scotch with Steve Shenker, and many discussions with the string theorists there who were concerned that they were getting bad publicity and didn’t know what to do about it. Some were concerned that Lubos Motl was not exactly representing them well.

Sean gives a fairly standard defense of the landscape (“maybe it really is the way the world works”), with no discussion of the main problem with the landscape, that it shows no signs of making falsifiable predictions that would make it legitimate science. Some other points of the discussion include speculation about “what if Feynman and Gell-Mann had blogs?”, and Sean’s analogy of the string/LQG debate with mainstream/”heterodox” academic economics.

Update: Sean has his own posting about this.

The public perception of string theory has definitely changed over the last few years, with the latest evidence this week’s cover story in New Scientist, which begins:

It’s the theory everyone loves to hate.

The article (available fully only to subscribers, I fear) is entitled String Theory: The Fightback, and its story line is that, because of all this criticism, after nearly 25 years of work, finally:

string theorists themselves have realised they must find ways to put their models to the test. They may still be far from being able to observe a string in a laboratory, but experiments planned for the near future – and even one currently under way – could provide tantalising evidence either for or against string theory…

Now the string community is fighting back by devising creative, if indirect, ways to look for signs of strings – from hidden dimensions to ripples in space-time and other potential signatures of a stringy universe. The time has come to put string theory to the test…

Critics should take heed. Experiments now show that string theory may be testable after all. One study at a time, string theorists seem to be homing in on models that will make specific, falsifiable predictions.

What follows is the usual misleading hype of bogus “tests” of string theory, of the sort I’ve written about extensively here. They are:

For one of my postings about this, see here. More than three years ago Polchinski and the KITP at Santa Barbara issued a press release about this trumpeting the idea that such superstrings could be observed by LIGO “over the next year or two.” The problem with this kind of “test” of string theory is that you can easily come up with string theory models that produce lots of cosmic superstrings (already falsified), no observable amount of cosmic superstrings (can’t use to test string theory), or precisely the amount of cosmic superstrings such that no hint of them would be seen until now, but there would be networks of the things lurking just below the threshold of measurability, to be discovered by the next generation of experiments (highly unlikely, pretty much pure wishful thinking). Polchinski has now stopped talking about LIGO and a year or two, and instead is promoting measurements of pulsars and five to ten years:

According to Polchinski, though, our best bet for observing gravitational waves emanating from strings is to use pulsars. A pulsar is a rapidly spinning neutron star that fires out a beam of electromagnetic radiation as it rotates, like a lighthouse. These flashing beacons act as some of the most accurate clocks in the universe, and a gravitational wave rippling between a pulsar and Earth would disturb the otherwise precise timing of the pulses arriving here. The most likely cause of such fluctuations would be black holes colliding, but waves from strings would yield a unique timing pattern that would make them stand out. “Over the next five to 10 years,” Polchinski says, “these [pulsar observations] will probe the most interesting models.”

My colleague Brian Greene is quoted about this, making the essential point about this kind of “test”:

Sure, catching sight of a cosmic string would be a boon for string theory, but is there any observation that would serve as a death knell? For many sceptics, it’s not that string theory is so hard to prove correct that puts them off, but rather that you can’t falsify it. “I’m not aware of any test that if it fails will prove string theory wrong,” says physicist Brian Greene of Columbia University in New York. “That’s a real headache. You’d like to have a situation where you have a prediction, and if it’s right the theory is right, and if it’s wrong the theory is wrong.”

The problem is that the quoted paper doesn’t actually say that. Here’s the paper’s concluding paragraph:

However, a possible discovery of tensor modes may force us to reconsider several basic assumptions of string cosmology and particle phenomenology. In particular, it may imply that the gravitino must be superheavy. Thus, investigation of gravitational waves produced during inflation may serve as a unique source of information about string theory and about the fundamental physics in general.

Given the wealth of possible string theory scenarios, I have no doubt that if an imprint of gravity waves is found in the CMB, there will be string theory models that would “predict” it. As for the idea that not seeing such gravity waves would be evidence for string theory, here’s what Glashow has to say:

Not everyone thinks these tests will be useful, however. “Not seeing something is hardly evidence for string theory,” says Nobel laureate Sheldon Glashow of Boston University, Massachusetts, an outspoken critic of string theory. He feels that such a result would mean very little. “String theorists are very wise. They can come up with a way to explain anything.” String theory is simply not testable, he says. “There are an enormous number of string theories and they describe zillions and zillions of universes, none of them observable in any way. It sounds to me like angels dancing on the head of a pin.”

“We’re still very far from being able to say, here is the exact string theory that describes QCD,” Susskind says. “But the connections that show up between nuclear physics and string theory are fascinating. Sceptics won’t consider this evidence for string theory, but nuclear physicists will use string theory and in time discover how accurately it describes these experiments.”

What Susskind is neglecting to mention here is that these are tests of whether string theory is a useful way to do calculations in an already tested theory of the strong interactions, and has nothing to do with the question of testing the idea of string theory as a unified theory of quantum gravity and particle physics.

Also in New Scientist, there’s a story about Neil Turok’s recent talk at PASCOS entitled “Is the Cold Spot in the CMB a Texture?” which links to the string theory article. Evidently there’s a patch of CMB where the temperature is anomalously low (the probability of this happening supposedly being 2 percent) and one can speculate that this may be due to a topological defect of some kind. Amusingly, the online version of the New Scientist article includes an interpolated editorial comment that someone forgot to take out before publication:

Turok presented the findings at a conference on particles Hi Anil. This threw me a bit. We say the team noticed previous work by Turok, and then before we know it Turok is the one presenting the work. When did he join them, strings and cosmology at Imperial College London last week.

I was on vacation for a while, but haven’t been posting much mostly since there’s not that much to write about. Like every summer, there are huge numbers of string theory conferences going on all over the world, but from looking at the talks that are available, the subject is about as dead as it has been for the last couple years, with essentially no new ideas. The reaction of string theorists to all the criticism that they have been getting in recent years about the lack of any connection of string theory to the real world seems to have been to rename their conferences things like String Theory and the Real World.

One other reason I haven’t been writing as much is that there are an increasingly large number of quite good math and physics blogs out there, run by other people who are doing a great job of writing about the kinds of news that I’ve often posted items about. There’s a mini-revolution going on in research-level mathematics blogging, with various Fields medalists being joined by groups of some of the best graduate students and post-docs around. Following on the heels of Berkeley’s wonderful Secret Blogging Seminar, there’s Cornell’s Everything Seminar and the Max Planck Institute in Bonn’s Vivatgasse 7 (mainly about arithmetic algebraic geometry).

Also at the Max Planck Institute, a couple weeks ago there was the yearly Arbeitstagung, a conference devoted to recent mathematics research and run in a somewhat unconventional way. The concept is to mostly not schedule talks and speakers in advance, but to instead just try and get a group of the best possible people to show up, and then to more or less democratically decide on who should speak about what, depending on who has something new to talk about. The first Arbeitstagung was organized by Friedrich Hirzebruch exactly 50 years ago, back in 1957, partly with the goal of bringing Germany back into the mainstream of mathematics research after the post-WWII period. Hirzebruch remained the organizer for many years (and was also director of Max Planck), and was there this year to give the opening lecture, on The first Arbeitstagungen in 1957, 1958 and 1962. At the first Arbeitstagung in 1957 some of the talks announced dramatic new results in mathematics, including the birth of K-theory. Grothendieck’s talk included the first definition and use of K-theory (of coherent sheaves on a projective algebraic manifold) in his proof of what is now known as the Grothendieck-Riemann-Roch theorem. Hirzebruch had worked some of this out more concretely before, and he reported on his work with Borel-Hirzebruch which links up representation theory, characteristic classes and topology in a fundamental way. Bott was not there, but had recently discovered Bott periodicity, and over the next few years Atiyah used this and the Dirac operator to reformulate Grothendieck-Riemann-Roch as a general index theorem in the context of differentiable manifolds, proving the theorem with Singer, and lecturing about it at the 1962 Arbeitagung. Hirzebruch gives an excellent description of some of this history. The talks are all available online, but I fear that there was nothing discussed this year that seems to reach the heights of what was being discovered back in those early days 50 years ago.

The latest news on the LHC schedule is: close the machine April 2008, beam commissioning starting May 2008, first beams at high energy July 2008, about exactly one year from now.

The Notices of the AMS has a wonderful set of articles this month about George Mackey, I wrote a bit about him here.

The Harvard string theory group will be minus not just Lubos Motl this coming year, but also Nima Arkani-Hamed, who will be on leave (I’m not sure where he’s going or what his plans are). I hear that the two of them had a joint goodbye party.

Starting today, Arkani-Hamed is pushing the multiverse at the String Theory and the Real World conference. For the hundredth puff-piece about how wonderful the anthropic multiverse pseudo-science is, see the article Islands in the Sea, at fqxi.org.

Bloomberg.com is carrying a review of Endless Universe, the recent Steinhardt/Turok book I wrote about here. The author of the review seems to have noticed the same thing about the book that I did:

Given the recent controversy surrounding string theory — the publication last year of Lee Smolin’s “The Trouble With Physics” and Peter Woit’s “Not Even Wrong” — it’s disturbing that Steinhardt and Turok don’t even address their dependence on it. Does their model work if string theory is wrong?

My sense is that it doesn’t, but they never even face the possibility — lending inadvertent weight to Smolin’s and Woit’s complaints that string theory is strangling physics. I hope the authors can someday publish a second edition in which they don’t treat string theory as the only game in town.

Despite its problems, string theory does now have a shop and a blog.

Update: The news is that Arkani-Hamed will be moving from Harvard to the Institute for Advanced Study.

Update: In case any one was worried that Lubos’s move back to Europe would end his entertainining rants about the stupidity of anyone expressing skepticism about string theory, don’t worry. The latest is Bloomberg: another idiotic article, which begins:

Elizabeth Lopatto is the name of the latest breathtaking idiot who was hired to write about theoretical physics for Bloomberg. I am periodically amazed that the newer journalists are always able to exceed the degree of mental breakdown of their predecessors.

and then goes on from there…

I’ve been finding recently that an increasing serious problems with blogs is that there are too many good ones with material worth reading. I’ve learned quite a lot recently from many well-informed blog postings, but the sheer number of these makes it hard to find the time for other things one should be doing.

I’ll violate my usual rule of sticking to math and physics and report that my brother Steve is joining me in the family blogging business by being involved as Publisher in a new venture that just launched this week called Xconomy. Basically it’s a blog based up in Cambridge, with offices in Kendall Square, devoted to news about what they call the “exponential economy”, that part of the economy responsible for what is perhaps too optimistically described as exponential growth in certain areas. They’re focusing on events and news relevant to new technology, especially bio-technology, businesses in the Boston area. For some interesting blog postings by their CEO Bob Buderi about what it’s like to start up this sort of business, see here and here. For a nice posting about Doc Edgerton, see here.

Back to physics and math, over at Backreaction there’s an excellent posting on the GZK cutoff and high energy cosmic ray experiments, and a report from Loops 07 sent in via Blackberry by Sabine Hossenfelder.

An American Physics Student in England tells about a recent conference on Heavy Flavour Physics, giving a very nice overview of what is going on in that field.

The latest This Week’s Finds in Mathematical Physics from John Baez is out (available here, blog entry and comments here). It’s a wonderful description of the various mathematical patterns that the standard model particles fit into. Most well known is what happens in SU(5) and SO(10) GUTs, where one can fit the fermion quantum numbers into something that can equivalently be described as the spinor representation in d=10, or the exterior algebra $\Lambda ^* (\mathbf C ^5)$. John goes on to explain various possible connections to the exceptional groups, including a recent idea from Garrett Lisi about how to use E₈ to get three generations.

The blog entry comments discuss two recent papers by Chamseddine and Connes about their non-commutative algebra approach to this question of mathematically characterizing the SM degrees of freedom. The papers are on the arXiv, entitled A Dress for SM the Beggar, and Why the Standard Model. Because of these papers and Witten’s recent one, John seems to be getting a bit more optimistic about physics, writing “I get the feeling that theoretical physics may not be quite so stagnant after all!”

All sorts of interesting stuff at the Secret Blogging Seminar, including yet more about Connes: a “review” by A. J. Tolland of the first quarter of the new book by Connes and Marcolli (available here), which A. J. claims has the title Noncommutative Geometry, Quantum Fields, Kitchen Sinks and Motives. Like the earlier fat book on non-commutative geometry by Connes, it’s an amazing document, ranging widely over physics and mathematics, covering ground from QFT to the Riemann hypothesis, at a level varying from expository sections on well-known subjects to more speculative research-level discussions. I’ve just started looking at it, may bring along a copy for summer vacation reading when I head up to a lake in New Hampshire tomorrow.

Other interesting things at the same blog include reports (here and here) from Ben Webster about talks by Sergei Gukov on categorification and gauge theory (about which he has a new expository paper here), as well as about an earlier talk by Gukov on Arithmetic Topology and Gauge Theory.

Also worth reading are posts from Ben Webster about centers of blocks of category O, various comment section discussions with David Ben-Zvi at both this blog and the n-category cafe, and a series of postings by David Speyer about quadratic reciprocity and geometric class field theory (I’m running out of energy to provide links…).

From Ben-Zvi (who could run a really great blog if he chose to…) there are notes from the recent conference at Northwestern on non-commutative geometry. These include an intriguing lecture by Beilinson, as well as lectures by Nadler and Ben-Zvi himself about their recent work which connects geometric Langlands with questions about more conventional representation theory using striking ideas about how to handle loop spaces. They have a recent paper about this, which has been very high on my list of things I wish I understood better ever since David gave an inspiring talk about this here a couple months ago.

Finally, one more thing definitely worth looking at in light of Witten’s new work: an expository and historical article by Jim Lepowsky about the story of the relation of vertex operator algebras and the monster group. He explains what is so remarkable about the specific vertex operator algebra that Witten is connecting to 3d gravity on AdS, including the ways in which it is conjecturally uniquely the “smallest” such structure in a specific sense.

Yesterday Sean Carroll and I appeared on the BBC Radio 4 program The Material World, in a segment on String theory – knot good enough?, about the controversy over string theory. The segment started with a piece from the play Humble Boy by Charlotte Jones, in which the main character is working on string theory. I don’t think anything either of us said was particularly controversial or would be in any way surprising to a regular reader of either of our blogs. The same program had a segment on the multiverse three weeks ago.

Some more titles of talks at next week’s Strings 07 have appeared. Witten’s talk is entitled “Three-Dimensional Gravity Revisited” and presumably will be about the new ideas described here. So, at least one talk there will be about a non-string theory approach to quantum gravity more along the lines of the LQG program. The schedule doesn’t seem to include any discussion session like the one at Strings 05 where the audience voted against the anthropic landscape.

A competing conference to Strings 07, Loops 07 will be taking place at the same time next week, but in Mexico, not Madrid. It’s much smaller, with less than a third as many participants. There will be one plenary talk on string theory, Moshe Roszali speaking on “Background Independence in String Theory”.

As the hunt for the Higgs is heating up at Fermilab, and CERN has officially announced the delay of LHC startup until next May, there’s a group of filmmakers who may be well-positioned if something exciting is found at the Tevatron. For the last few years 137 Films has been making a film to be called The Atom Smashers, following scientists working at FNAL. Filmmaker Clayton Brown is keeping a blog about this.

Yet another bogus “possible [experimental] signature for string theory”. Even Lubos doesn’t seem to believe this one, so I’ll just quote his argument:

My personal guess based on our work on the weak gravity conjecture is that the black hole bound is also satisfied in string theory for localized macroscopic objects, up to small corrections. This belief of mine is supported by the observation that Gimon & Hořava don’t have any explicit solution for their “superspinar”.

Christina Sormani tells me she has created a Wikipedia article on the proof of the Poincare conjecture, see here. For the latest on Perelman, see here.

Experimenters at the Tevatron have released data showing the existence of a new baryon, built out of a down, strange and bottom quark, and having a mass of 5.774 +/- .019 GeV. It has been given the name “Ξ_b“. The FNAL press release is referring to this as a “triple-scoop” baryon, since it contains one quark from each of the three generations. Tommaso Dorigo has a new posting about this.

Postings on this blog tend to involve a certain amount of discussion of bad behavior by theorists, so I guess I should point out here that this story comes with some accusations of less than good behavior by experimentalists in the way this was announced. The press release is all about the announcement of this discovery by the D0 experiment, and about their paper, which was submitted to the arXiv Tuesday night. It turns out though that D0’s competition, CDF, also has had the same result for a while, and it had already been “blessed” but not officially announced. So CDF was “scooped” at the last moment for the “triple-scoop”, and I imagine there are dark accusations going around about how D0 might have found out about this and rushed out the paper and press release. Supposedly there is an informal one-week notification period that the two experiments normally observe to keep this kind of thing from happening. Anyway, looks like they’re trying to fix it up a bit: the FNAL web-site contains a “special announcement” of back-to-back seminars about this, D0 at 1pm, which will “immediately be followed” by a CDF seminar. The D0 seminar is called

First observation of a new b-baryon, Ξ_b

whereas the CDF seminar is entitled

Observation of a new b-baryon, Ξ_b