In order to describe properties of an equilibrated quark-gluon plasma, QCD at finite temperature (and density) has to be considered. Besides lattice calculations, which can be applied only to static quantities at zero density, perturbative QCD has been used. At finite temperature, however, serious problems such as infrared divergent and gauge dependent results have been encountered. These diffi...

In order to describe properties of an equilibrated quark-gluon plasma, QCD at nite temperature (and density) has to be considered. Besides lattice calculations, which can be applied only to static quantities at zero density, perturbative QCD has been used. At nite temperature, however, serious problems such as infrared divergent and gauge dependent results have been encountered. These di cultie...