Thermalization with non--zero initial anomalous quantum averages

Abstract

We discuss the thermalization process in the kinetic approximation in the presence of non--zero initial anomalous quantum expectation values on top of an initial non--planckian (non--thermal) level population. Namely we derive a system of "kinetic" equations for the level population and anomalous expectation values in four--dimensional massive scalar field theory with $\varphi^4$ self--interaction. We show analytically in the linear approximation that for their small initial values the anomalous quantum averages relax down to zero. Furthermore, we show analytically that this system does not have an equilibrium solution with non--zero time independent anomalous expectation value.