A Projection Operator Approach to Extended Irreversible Thermodynamics

Abstract

Based on the projection-operator formalism established by Mori for Langevin equations, a general theory is formulated which is applicable to the description of transient irreversible processes. A time-smoothed density matrix (previously discussed by the present author) is used to define the projection operator in place of the equilibrium density matrix in Mori's formalism. It is shown that a statistical mechanical theory for transient processes can be developed in our formalism that dovetails perfectly with extended irreversible thermodynamics.