Leading large N modification of QCD₂ on a cylinder by dynamical fermions

Abstract

We consider two-dimensional QCD on a cylinder, where space is a circle. We find the ground state of the system in case of massless quarks in a 1/N expansion. We find that coupling to fermions nontrivially modifies the large N saddle point of the gauge theory due to the phenomenon of "decompactification" of eigenvalues of the gauge field. We calculate the vacuum energy and the vacuum expectation value of the Wilson loop operator both of which show a nontrivial dependence on the number of quarks flavours at the leading order in 1/N.