Abstract

I will discuss a recent proposal that may give a way to study the finite-density physics of large N QCD on the lattice, by using some special properties of the large N limit to dodge the fermion sign problem in large N QCD . The proposal is based on the observation that SO(Nc) gauge theory with Nf fundamental Dirac fermions does not have a sign problem at finite baryon number chemical potential μB. One can thus use lattice Monte Carlo simulations to study this theory at finite density. The relevance of this to large N QCD , an SU(N) gauge theory, is that a wide class of observables in the SO(Nc) theory coincide with observables in QCD in the large N limit, as can be shown using the technique of large Nc orbifold equivalence. I will argue that the orbifold equivalence between the two theories continues to hold at μB ≠ 0 provided one modifies the SO(Nc) theory in a certain way. This opens up the prospect of learning about QCD at μB ≠ 0 using lattice studies of the SO(Nc) theory.