Nuclear Physics & RIKEN Theory Seminar
"Sneaking up on dense QCD using large N methods"
Presented by Aleksey Cherman, University of Minnesota
Friday, March 15, 2013, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Vladimir Skokov
Finite-density QCD notoriously suffers from the fermion sign problem, which makes lattice Monte Carlo simulations impractical. As a result, we do not have much non-perturbative information about the behavior of QCD at finite baryon number density. I will discuss a proposal to dodge the sign problem by exploiting orbifold equivalence, a property of the large N limit of QCD. The proposal starts with the observation that if the gauge group of QCD is changed from SU(N) to SO(N), the sign problem does not appear at finite baryon number chemical potential, and the resulting theory can be studied on the lattice. Despite this seemingly drastic change, it turns out that there is a large N orbifold equivalence between the SO(N) theory and SU(N) QCD. I will argue that the equivalence will hold at finite quark-number chemical potential, where the SU theory has a sign problem but the SO theory does not. This opens up the prospect of learning about QCD at finite baryon number density using lattice studies of the SO(N) theory, at least in the large N limit.