On the General Definition of the Production of Entropy in Open Markov Quantum Systems

Abstract

We discuss the question of the general definition of the production of entropy per unit time for a quantum system governed by the Lindblad equation. The difficulty is as follows: in order to determine the total production of entropy, one must know the entropy flow from the system into the environment. This requires additional information on the environment and on its interaction with the system. The Lindblad equation for the reduced density matrix of the system does not contain such information. Therefore, the following question arises: What minimum additional information about the environment must be added to the Lindblad equation in order to find the flow of entropy into the environment and the total production of entropy? To answer this question, we use the concept of a complementary quantum channel known from the the quantum information theory. We also prove a theorem on the nonnegativity of production of entropy, and, under certain assumptions, the adiabatic and nonadiabatic contribution to it.