Self-energy-functional approach to systems of correlated electrons

TL;DR

This paper introduces a self-energy-functional approach for correlated electron systems, enabling non-perturbative, thermodynamically consistent approximations through a variational scheme, with demonstrated numerical effectiveness.

Contribution

It presents a novel variational method based on the self-energy functional for studying correlated electrons, improving upon existing approximation techniques.

Findings

Numerical results confirm the method's practicality.

The approach provides a thermodynamically consistent framework.

It enables construction of new non-perturbative approximations.

Abstract

The grand potential of a system of interacting electrons is considered as a stationary point of a self-energy functional. It is shown that a rigorous evaluation of the functional is possible for self-energies that are representable within a certain reference system. The variational scheme allows to construct new non-perturbative and thermodynamically consistent approximations. Numerical results illustrate the practicability of the method.