A hierarchy of equations for finite temperature Green functions

Lambert, Colin (1981) A hierarchy of equations for finite temperature Green functions. physica status solidi (b), 107 (2). pp. 435-441. ISSN 0370-1972

Abstract

Employing a new theorem on time ordered products of operators, an infinite hierarchy of equations for the finite temperature Green functions of a many particle system is obtained. The analysis provides a basis for the extension to finite temperatures of recent results from ground state perturbation theory. The connection between the present analysis and the corresponding ground state formalism is briefly discussed.