Kinetic equations for the quark-gluon plasma and their semiclassical expansion

Abstract

On the way towards a dynamical description of quark-gluon plasma (QGP) generated in heavy ion collisions, we have to take care of both gauge theoretical and non-equilibrium problems. We present a reformulation of Wigner-operators and their quantum kinetic equations with emphasis on the idea of physical phase space. We show how to separate the dynamical contents of these equations from purely gauge theoretic information which can be eliminated by a suitable choice of gauge. This provides the basis for a systematic semiclassical expansion which is compatible with standard QCD perturbation theory. We also establish and discuss ‘linear’ kinetic equations on an equal footing with the so far more familiar ‘quadratic’ ones.