On the evolution of quantum non-equilibrium in expanding systems

Abstract: We consider a particle confined in a uniformly expanding two-dimensional square box from the point of the view of the de Broglie-Bohm pilot-wave theory. In particular we study quantum ensembles in which the Born Law is initially violated (quantum non-equilibrium). We show examples of such ensembles that start close to quantum equilibrium, as measured by the standard coarse-grained H-function, but diverge from it with time. We give an explanation of this result and discuss the possibilities that it opens.