Progress on increasing luminosity at the LHC has been going extremely well, with peak luminosity a few moments ago over 7×1032cm-2s-1. So far integrated luminosity is over 200 pb-1, well on the way to the extremely conservative nominal goal for the year of 1000 pb-1. By fall, with the shutdown of the Tevatron at the end of FY 2011, the LHC experiments should be in a position to start overtaking the Tevatron and seeing evidence of a standard model Higgs if it is there.
It’s still very early to know how Fermilab will do in the US FY2012 budget, other than that the Tevatron will definitely not be there. However, the Obama administration is supportive in its budget proposal, and this document from the Republicans running the relevant House committee is encouraging for HEP research. Democrats and Republicans seem to agree that science research is a good thing in general, and HEP research is not one of the categories that annoys Republicans and that they suggest cutting (applied research that could be done by private companies, climate science research, environmental research, ITER). One member of the committee is freshman Republican Randy Hultgren, who represents the district that includes Fermilab, and he added his own addendum to the report, emphasizing support for HEP research. Hopefully the Republicans will want to help re-elect him by getting him anything he asks for…
With the bizarre US budgeting process of recent years though, whatever the appropriate Congressional Committee decides may turn out to be irrelevant, with last minute budget cuts appearing from mysterious sources to get things under whatever numbers end up being agreed to.
The New Yorker has a profile this week of David Deutsch. I still can’t figure out what his argument is that if a quantum computer works, that means there are multiple universes.
Lots of people are asking me what I think of ‘t Hooft’s new paper. The answer so far is just that I don’t understand it. He’s doing something unusual with how he handles conformal symmetry, and I think one needs an expert on that to weigh in.
Mathoverflow continues to amaze me, providing the sort of high-quality discussion that the internet was always supposed to provide, but rarely did. For example, see this recent question, which asks about the relationship between two different ways of encoding the geometry of a manifold. One way to do this is to choose a metric, the other is to choose a connection on the frame bundle. For arbitrary bundles, there’s an infinity of possible connections and they have nothing to do with the metric, but the frame bundle carries extra structure (the vierbeins, in physicist’s language). Given a metric, this extra structure can be used to pick out a unique connection (called the Levi-Civita connection), which satisfies two conditions: orthogonality and zero torsion. The question asked is about whether one can go the other way: given a connection, is there a unique metric for which it is the Levi-Civita connection?
The answers given include one by Fields Medalist Bill Thurston, whose comments reflects his background as a topologist, another is by MSRI director Robert Bryant, whose answer is that of a geometer, one who has delved deeply into the subject, including its roots in the work of Elié Cartan. The fact of the matter is that the relationship between these two structures is not one-to-one, for reasons that are well explained. This may be of interest to physicists thinking about the quantization of gravity. In that subject, one basic question is that of which fundamental variable to pick to “quantize”, and the conventional choice is the metric, even though in non-gravitational physics, the conventional choice is the connection. Philosophically though, the gauge symmetry involved in gravity is something like local translation symmetry, and the right analogy of a Yang-Mills connection might be not a connection on the frame bundle, but something like the vierbein, but that’s a whole other story….