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 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.
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.
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…