Taking off tomorrow for a long weekend, internet access may be spotty. Here are some things that may be of interest:
HEPAP is meeting today and tomorrow, the presentations given at the meeting are available here. JoAnne Hewett is there and has a posting on Cosmic Variance.
The Seed article with various physicist’s views about what to expect at the LHC that was discussed here earlier is now available online.
There’s an article about Jim Simons in Newsday (via Angry Physics).
Maybe a cosmologist can comment on the significance of this, but over at CosmoCoffee there’s a discussion of a new paper reanalyzing the latest WMAP data and coming up with a scalar spectral index ns= .969 +/- .016. This is now 2.0 sigma away from 1, instead of the 2.7 sigma of the earlier analysis. This deviation from 1 was widely sold as evidence for inflation (since the simplest inflationary models give values slightly less than one), the fact that it is now only a 2 sigma effect seems to make this case a bit weaker.
Bruno Kahn has an excellent expository article on motives.
Over at the Edge web-site Lawrence Krauss has a piece called The Energy of Empty Space That Isn’t Zero. It’s partly about the cosmological constant, and discusses a workshop on Confronting Gravity that he organized back in March, which brought many prominent theorists together at a Caribbean resort to discuss physics, travel in a submarine, and hang out at the “private island retreat” of the funder of the event, science philanthropist Jeffrey Epstein.
Krauss has many provocative things to say about the current state of theoretical physics, including perhaps the most concise and vivid description I’ve read in a while:
It’s been very frustrating for particle physicists, and some people might say it’s led to sensory deprivation, which has resulted in hallucination otherwise known as string theory.
He also has a somewhat longer skeptical take on extra dimensions, together with an attempt at positive spin:
Many of the papers in particle physics over the last five to seven years have been involved with the idea of extra dimensions of one sort or another. And while it’s a fascinating idea, but I have to say, it’s looking to me like it’s not yet leading anywhere. The experimental evidence against it is combining with what I see as a theoretical diffusion — a breaking off into lots of parts. That’s happened with string theory. I can see it happening with extra-dimensional arguments. We’re seeing that the developments from this idea which has captured the imaginations of many physicists, hasn’t been compelling.
Right now it’s clear that what we really need is some good new ideas. Fundamental physics is really at kind of a crossroads. The observations have just told us that the universe is crazy, but hasn’t told us what direction the universe is crazy in. The theories have been incredibly complex and elaborate, but haven’t yet made any compelling inroads. That can either be viewed as depressing or exciting. For young physicists it’s exciting in the sense that it means that the field is ripe for something new.