Dynamical typicality of embedded quantum systems
AbstractWe consider the dynamics of an arbitrary quantum system coupled to a large arbitrary and fully quantum-mechanical environment through a random interaction. We establish analytically and check numerically the typicality of this dynamics, in other words, the fact that the reduced density matrix of the system has a self-averaging property. This phenomenon, which lies in a generalized central limit theorem, justifies rigorously averaging procedures over certain classes of random interactions and can explain the absence of sensitivity to microscopic details of irreversible processes, such as thermalization. It provides more generally an ergodic principle for embedded quantum systems.