Correlation operators in many-particle physics

Abstract

Correlation functions and thermodynamic Green's functions are expressed as matrix elements of corresponding superoperators. A connection between the super-operator formalism, which has been used extensively in relaxation problems and in magnetism in recent years, and the method of thermodynamic Green's functions is thus established. The introduction of correlation (super-) operators describing dynamical as well as statistical aspects of a physical system allows for an abstract formulation of the theory independent of any special representation which results in considerable formal simplifications.

The investigation of the Laplace-transformed correlation operator leads to Dyson's equation with the self-energy explicitly expressed as a superoperator matrix element.