Temperature Dependence of the Chiral Condensate from an Interacting Pion Gas

Abstract

By exploiting the fact that the chiral condensate is related to the derivative of the free-energy density with respect to the bare quark mass we calculate the temperature dependence of the condensate ratio $\text{ave}{\bar{q}q}_T/\text{ave}{\bar{q}q}_0$ from an iteracting pion gas. When using the Weinberg Lagrangian at the Hartree level we find a depression of the condensate with temperature. For $T<100$ MeV the results are in good agreement with chiral perturbation theory in the three loop approximation. Near $T_c$, however, there are marked differences due to non-perturbative nature of our approach.

Comments: 8 pages LATEX plus 4 figures available from the authors, preprint KFA-IKP(TH)-1994-22