QCD at finite temperature—a variational approach

Abstract

We develop here a nonperturbative framework to study quantum chromodynamics (QCD) at finite temperatures using the thermofield dynamics (TFD) method of Umezawa. The methodology considered here is selfconsistent and variational. There is a dynamical generation of a magnetic gluon mass. This eliminates the infrared problems associated with perturbative QCD calculations at finite temperatures. We obtain here the thermodynamical quantities like free energy density, pressure and entropy density. We also calculate the temperature dependence of SVZ parameter\(\frac{{\alpha _s }}{\pi }\left\langle {G_{\mu v}^a G^{a\mu v} } \right\rangle \). The condensate vanishes at the critical temperature in accordance with recent hot sum rule calculations. The present method gives an insight to the vacuum structure in QCD at zero temperature as well as at finite temperatures in a coordinated manner.