Instanton fermionic zero mode at finite temperature and chemical potential

Abstract

The spontaneous breaking of chiral symmetry and the U(1) axial anomaly in QCD, can be phenomenologically understood by considering instantons as the gauge configurations mediating quarkquark interaction. The existence of an exact zero mode solution of the Dirac equation in the field of a single instanton is the fundamental ingredient. Explicit expressions for ψ0 are available for T = 0 and µ = 0, and µ = 0 and T = 0. In this paper we derive the solution for the most general case T = 0 and µ = 0. This opens the possibility of investigating the QCD dynamics associated with instantons in the full phase diagram. As a first step in this direction, we will study the dependence of the instanton density from the thermodynamic coordinates.