The Propagator Matrix and the Quenched Approximation at Finite Baryonic Density

Abstract

Simulations of QCD at finite baryonic density on the lattice have given results which are in complete contradiction to theoretical ideas. It is expected that there will be a chiral symmetry restoration phase transition at nuclear density. I.e. at a chemical potential µ equal to about a third of the nucleon mass (1/3)m_N. Monte carlo simulations have however shown a transition at a lower density consistent with a critical µ equal to half the pion mass (1/2)m_π ⁽¹⁾.