Quasithermodynamic Representation of the quantum master equations: its existence , advantages and applications

We propose a new representation for several quantum master equations in so-called quasithermodynamic form. This representation (when it exists) let one to write down dynamical equations both for diagonal and non-diagonal elements of density matrix of the quantum system of interest in unified form by means of nonequilibrium potential ("entropy") that is a certain quadratic function depending on all variables describing the state. We prove that above representation exists for the general Pauli master equation and for the Lindblad master equation ( at least in simple cases ) as well. We discuss also advantages of the representation proposed in the study of kinetic properties of open quantum systems particularly of its relaxation to the stationary state.