Not Even Wrong

Two new books from Cambridge that are now available:

A First Course in String Theory by Barton Zwiebach, based on a course on string theory for undergraduates taught at MIT. It’s available for \$42 at Barnes and Noble, sales rank 565, for \$60 at Amazon, sales rank 13,559. The whole idea of trying to teach a very speculative theory that hasn’t really worked and which is based on 2d quantum field theory to undergraduates seems to me to be utter lunacy. But maybe I’ll even buy a copy.

Topology , Geometry and Quantum Field Theory, the proceedings of a symposium that I went to at Oxford in 2002 in honor of Graeme Segal’s 60th birthday. This conference had some wonderful talks and I’m looking forward to reading many of the contributions. Supposedly it also contains Segal’s manuscript “The Definition of Conformal Field Theory”, which has been circulating in samizdat for years. My copy (which like many others contains the hand-written notation “Do Not Copy” on the front) is falling apart, yet another reason why I just ordered the book, even though it is \$90. The story I heard is that Segal didn’t want his manuscript reproduced, but finally agreed on the condition that it not be re-typeset, but appear exactly as in the original, so that it would be clear that it was still something preliminary and tentative, with no corrections or improvements made since he wrote it.

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.