Exact dynamics and thermalization of open quantum systems coupled to reservoirs through particle exchanges

In this paper, we study the exact dynamics of general open systems interacting with their environments through particle exchanges. The paper includes two main results. First, by taking advantage of the propagating function in the coherent state representation, we obtain the exact solution of the reduced density matrix, which is expressed in terms of the nonequilibrium Green functions. Second, in the dynamical perspective, we provide a rigorous thermalization process of open quantum systems.