StatisticalMechanical Theory of Irreversible Processes. I
Abstract
A general type of fluctuationdissipation theorem is discussed to show that the physical quantities such as complex susceptibility of magnetic or electric polarization and complex conductivity for electric conduction are rigorously expressed in terms of timefluctuation of dynamical variables associated with such irreversible processes. This is a generalization of statistical mechanics which affords exact formulation as the basis of calculation of such irreversible quantities from atomistic theory. The general formalism of this statisticalmechanical theory is examined in detail. The response, relaxation, and correlation functions are defined in quantummechanical way and their relations are investigated. The formalism is illustrated by simple examples of magnetic and conduction problems. Certain sum rules are discussed for these examples. Finally it is pointed out that this theory may be looked as a generalization of the Einstein relation.
 Publication:

Journal of the Physical Society of Japan
 Pub Date:
 June 1957
 DOI:
 10.1143/JPSJ.12.570
 Bibcode:
 1957JPSJ...12..570K