Not Even Wrong

Witten is lecturing at a conference in Crete this week and some of his transparencies are already online. He is talking about perturbative gauge theory amplitudes and the idea of interpreting them in terms of strings in twistor space. He motivates this by noting that AdS/CFT is useful for understanding gauge theories at large g^2N, but at short distances asymptotic freedom implies g^2N is small and to understand gauge theory in terms of strings you need to do so for all g^2N. He warns “I can’t promise that what I’ll explain will turn out ot be useful in a string description of QCD, but at least I’ll tell you interesting things about perturbative gauge theory!”.

For something completely different, the latest on the Landscape is that, at least this week it predicts low energy supersymmetry, maybe.

There a new article on Slate about string theory and my colleague Brian Greene. Also some commentary about it on David Appell’s weblog Quark Soup.

Michael Atiyah and Graeme Segal have a new foundational paper out on twisted K-theory. It doesn’t have too many examples or applications, but lays a rigorous foundation for a certain point of view on the subject. Section 5 is the one quantum field theorists should pay attention to, it explains the relation to the fermionic Fock space. For a more explicit construction relating QFT to twisted K-theory, besides the papers of Freed, Hopkins and Teleman, one can look at “Gerbes, (twisted) K-theory, and the supersymmetric WZW model” by Jouko Mickelsson.

Throughout the mid-to-late 80s, the NSF and other organizations would periodically issue alarmist reports about an impending dangerous shortage of scientists and engineers in the U.S. These projections for shortages turned out to be utter nonsense, as anyone who looked at the situation honestly could have foreseen. By the early 90s, instead of a shortage, the bottom dropped out of the employment market for scientists. In the math department here I saw a large number of very good graduate students and post-docs leave the field because there were no jobs for them.

Particle theory is a field in which the job market has been varying degrees of awful since about 1970. One might argue that while this is tough on young particle theorists, it means that the few who get jobs will be truly outstanding and the subject will flourish. The problem with this argument is that particle theory has seen extremely little progress since the mid-70s, about the time that one would expect the effects of the tight job market to be seen. The main reason for this is that the standard model is just too good, but one could plausibly argue that the evidence is that a very tight job market is bad for the field. Good people don’t go into it; those that do and survive do so by not working on anything too ambitious, because it could easily fail and they’d be out on the street.

Mathematics is a much more normal job market than particle theory, but there still have always been a lot more Ph.D.s than jobs where they can use their talents. The job market in math was terrible in the early-to-mid nineties, got better in the late-nineties and is not so bad now. Our students seem to be doing relatively well at getting jobs. Budgets are tight, especially at state universities, but a lot of people hired during the 60s are finally starting to retire.

The NSF is now at it again, with its National Science Board issuing a glossy report entitled An Emerging and Critical Problem of the Science and Engineering Labor Force. A good article in the Chronicle of Higher Education reports on this, but also has a lot of information debunking the report.

Why does the NSF repeatedly engage in this kind of alarmism and dishonesty? If you take a look at the membership of the National Science Board, you’ll find no young scientists, but a lot of university and NSF administrators, corporate executives, and senior professors. All of these people have a large vested interest in flooding the scientific labor pool in the U.S. so that it will provide a lot of cheap labor. The NSF gets much of its funding from Congress by emphasizing its role in training scientists, so of course it wants to claim that more of this needs to be done. Universities and corporations want lots of new Ph.D.s so they can get the best ones to work for them for peanuts. Universities want lots of grad students to provide cheap labor as TAs. Senior professors, at least in the experimental sciences, want lots of grad students to staff their labs cheaply. These people all seem to firmly believe that a system that produces huge numbers of underemployed and badly paid young scientists is the best thing for science and for the U.S. as a whole. In fact, it is just the best thing for their personal interests.

The buzz is that Hawking has a new idea about how to resolve the “Black Hole Information Paradox”, the well known incompatibility between standard ideas about black holes and the unitary time evolution of the wave function that is fundamental to quantum mechanics. Evidently Hawking has asked to give a talk about this at GR17, a big conference on general relativity that will be held July 18-23 in Dublin.

The abstract for his talk goes like this:

“The Euclidean path integral over all topologically trivial metrics can be done by time slicing and so is unitary when analytically continued to the Lorentzian. On the other hand, the path integral over all topologically non-trivial metrics is asymptotically independent of the initial state. Thus the total path integral is unitary and information is not lost in the formation and evaporation of black holes. The way the information gets out seems to be that a true event horizon never forms, just an apparent horizon.”

I can’t tell exactly what that means either, so I guess we’ll have to wait for the talk. My own prejudice about quantum field theory is that the relation between the Euclidean and Minkowski space formulations of quantum field theory is actually much more interesting and subtle than people think. It’s not just a technical trick. So I’ll be interested to see what Hawking has to say about this.

Something else at the conference that may be interesting will be Sir Roger Penrose’s public talk entitled “Fashion, Faith and Fantasy in Modern Physical Theories”. Guess what he is referring to by “Fashion”.

One contributor to the comments here (JC) has pointed out that Susskind has withdrawn from the arXiv his recent paper on the stupendous Landscape of sting theory. This is pretty unusual, but often when it happens the author puts in the withdrawal statement some indication of why the paper was withdrawn, something Susskind didn’t do in this case. Another contributor to the comments (Serenus Zeitblom) points out that one should look at recent changes to Douglas’s paper on the arXiv, which is now up to its fourth version.

One feature of the arXiv is that all posted versions of papers are available, so one can compare them and see what changes the author made. The history of Douglas’s paper is quite something. The original version was posted on May 30. Susskind’s now withdrawn paper was posted on June 17, and in it he claims that Douglas’s paper showed that Susskind’s argument in an earlier (May 21) paper (which exists in three versions) was wrong. The latest version (4) of Douglas’s paper now says that earlier versions of the paper are wrong. So, one reason Susskind withdrew his paper is presumably that its claims that his earlier paper was wrong were now wrong because they were based on Douglas’s wrong paper. Got that? This all seems to me to be a new and original version of the “Not Even Wrong” phenomenon.

Some other high points of the changes in the four versions of Douglas’s paper:

1. Going from version 1 (May 30) to version 2 (June 2), he changes

“If I had to bet at the moment, I would still bet that string theory favors the low scale, for the reasons outlined above, but it is not at all obvious that this is what will come out in the end.”

to

“At this point, it is not at all obvious whether high or low scales will be preferred in the end.”

2. Going from version 2 (June 2) to version 3 (June 22), he adds a reference to Susskind’s June 17 paper, some criticism of it, and the sentence

“The correct assumptions could be determined from string/M theory considerations with more work, and we are optimistic that this can be done in time to make convincing predictions before LHC turns on in 2007.”

3. Going from version 3 (June 22) to version 4 (June 29), he removes the sentence above (I guess he became less optimistic last week) and announces that the argument in the previous versions was wrong.

Some of the talks given at the Lattice 2004 conference are now available on-line. Particularly interesting is Kenneth Wilson’s historical talk about his roles in the development of the renormalization group and of lattice gauge theory. He also refers to the website of the Dibner Institute.. One interesting thing there is a collection of materials relevant to the history of the renormalization group.

The Dibner Institute is at MIT, but during my high school days I recall visiting the library for the history of science that Bern Dibner had founded which was located close to where I lived, in Norwalk, Connecticut. The collection was moved up to Cambridge after Dibner’s death in 1988.

It seems that the Fermilab Tevatron is a quite sensitive detector for earthquakes. According to the Accelerator Update for yesterday, a small earthquake in Illinois caused the machine to lose its beam and a superconducting magnet to quench. A few hours later, a more significant earthquake in Alaska was quite visible to the Tevatron accelerator operators, and would have caused another quench, but they hadn’t restored the beams yet.

Two of the year’s largest particle theory conferences are taking place around now, with Lattice 2004 attracting 280 physicists to Batavia, Illinois this past week and Strings 2004 drawing almost 500 to Paris starting tomorrow. Normally I feel kind of sorry for string theorists since their field is in such bad shape, but this week I’m jealous since I would have loved to have an excuse to go to Paris this summer (I’m not jealous of the lattice gauge theorists who are getting to spend the week in Batavia).

Maybe I’m wrong about this, but the Paris string theory conference seems to me to be the largest gathering of particle theorists that I can remember ever having taken place. In recent years these things have been huge, with attendance around 400-450, but this one should be even larger. It is so over-subscribed that they haven’t been taking on-line registrations for weeks.

Both conferences should have transparencies from the talks available soon on-line and the list of titles and speakers in Paris is now available. Some of the ones that look like they might be interesting are Robbert Dijkgraaf speaking about “Topological M-theory”, Nikita Nekrasov on “Chasing M/F theory” and maybe Greg Moore, whose title is the mystifying “Anomalies, Gauss laws, and Page Charges in M-theory”. One big theme of the conference looks like it will be N=4 super Yang-Mills theory. This is an interesting and well-defined quantum field theory, and one can study it whille claiming to be a string theorist because of the AdS/CFT conjecture and Witten’s recent work reformulating it in terms of topological strings in twistor space.

Next Saturday in Paris there will be a whole day of talks devoted to the unrelenting hyping of string theory to the general public, something which is a standard feature of the “Strings XXXX” conferences, but not the “Lattice XXXX” ones. Somehow I suspect the speakers will neglect to emphasize the utter lack of any progress towards making any contact with reality during the past twenty years. In case the Paris conference is not enough, there are quite a few satellite conferences, including a pre-conference workshop at the IHES and post-conference workshops at CERN and Durham.

Update: It looks like Jacques Distler will be reporting direct from the conference.

Further Update: It seems that they have a WiFi connection at the Paris conference site. From my web server logs, it appears that one thing attendees at the conference are doing during the more boring talks is reading “Not Even Wrong” on the web. Hi Guys!