Thursday, January 19, 2006

More Miscellanea

At some point I should do a real post (e.g. on lattice fermions and/or on improved actions) again, but for now I will stick with these cheap multi-link posts.

The first item in this one is actually not a link, but an announcement. Matthew has left the quanta behind to become a quant himself -- he now works in a city job in London. We all wish him the very best for his new career, and hope that he will still occasionally find the time to contribute to the lattice world and the physics blogosphere.

The second item is a new experimental determination of the top quark mass published in Physical Review Letters by the CDF collboration, significantly reducing the errors on the top quark mass. Of course, the top quark is so heavy that it never really plays a role in lattice computations.

The third item is a theory paper in which the AdS/CFT correspondence is used to calculate hadronic masses (with mixed success). It is a little funny to see string theory, with all its grand claims to be the TOE (relegating QCD to the status of an effective theory at "low" energies), return as an effective model for the strong interactions (where there is little doubt that QCD is the fundamental theory).

The fourth item is a bit odd. We all know Vector Calculus, of course, and some will know, or have heard of, Regge Calculus, Spinor Calculus and even Lambda Calculus; but what on earth is Bikini Calculus?!? Turns out it is a series of videos with girls in bikinis teaching basic calculus, presumably in order to get the more hormone-driven among the male students interested in the subject. I'm not entirely sure if that is going to work (or even if it is entirely desirable), but I suppose anything that gets past the strange prejudices North American students (I have never seen the same "it's too hard and incomprehensible" attitude with regards to calculus in Europe) seem to have about calculus is a good thing. The site which sells the videos is called www.howtodogirls.com, and I assume that the parsing ambiguity between the intended {{How To Do} Girls} and {How to {do girls}} is entirely intended by the owners.

The fifth item is very brief again. I have created a new area in the sidebar, which is to contain links to series of thematically related posts on this blog. Unfortunately, Blogger doesn't allow categorization of posts, so it will have to be updated by hand, which may mean some delay between a new series item being posted and appearing in the sidebar.

2 comments:

Anonymous said...

The third item is a theory paper in which the AdS/CFT correspondence is used to calculate hadronic masses (with mixed success). It is a little funny to see string theory, with all its grand claims to be the TOE (relegating QCD to the status of an effective theory at "low" energies), return as an effective model for the strong interactions (where there is little doubt that QCD is the fundamental theory).

But surely all the dualities between quantum field theories (and string theory) make the notion of "fundamental" untenable?

Georg said...

But surely all the dualities between quantum field theories (and string theory) make the notion of "fundamental" untenable?

Well, I guess it depends what you mean by "fundamental": Does it mean "true at all energy scales"? Then we probably don't have a fundamental theory of anything, and maybe there isn't even one in principle. Or is it merely a relation "more fundamental than" <-> "reducible to" or maybe "less fundamental than" <-> "an approximation of"? In that case dual theories would be equally fundamental, but e.g. Chiral Perturbation Theory would still be less fundamental than QCD. This latter notion is certainly tenable within the framework of effective field theories, and it was this latter sense in which I meant that QCD is the fundamental theory of the strong interactions. To the best of my understanding there is no string theory that is exactly dual to QCD; and whatever CFT has a string dual is at best an approximate model for QCD, making QCD the "more fundamental" theory compared with string theories of the strong interactions.