Thursday, April 19, 2007

Some quick links

Superweak has an interesting post on blind analysis, which is the first technique that has been carried over from medicine into nuclear and particle physics (rather than the other way, as were NMR, PET and a host of others). More on blind analysis techniques in experimental particle physics can be found in this review. Reading this, I was wondering wether any lattice groups used blinding in their data analyses; I am not aware of any that do, and the word "blind" does not appear to occur in hep-lat abstracts (except for phrases like "blindly relying on" and such). It may not be necessary, because we don't do the same kind of analyses that the experimenters do (like imposing cuts on the data), but the possibility of some degree "experimenter's (!?) bias" may still exist in the choice of operators used, priors imposed on fits etc.

There is a new paper on the arXiv which reports on tremendous gains in simulation efficiency that the authors have observed when using a loop representation for fermions instead of the conventional fermion determinant. Unfortunately their method does not work with gauge theories (except in the strong coupling limit) because it runs into a fermion sign problem, so it won't revolutionise QCD simulations, but it is very interesting, not least because it looks a lot like some kind of duality (between a theory of self-interacting fermions and a theory of self-avoiding loops) is at work.