Dynamical susceptibilities in strong coupling approach: General scheme and Falikov-Kimball model

TL;DR

This paper develops a general method within dynamical mean field theory to compute dynamical susceptibilities in strongly correlated electron systems, exemplified by analytical results for the Falicov-Kimball model.

Contribution

It introduces a new scheme based on an expansion around the atomic limit for calculating susceptibilities in strongly correlated systems.

Findings

Analytical expressions for susceptibilities in the Falicov-Kimball model.

Applicable to models with strong electron correlations.

Provides a systematic diagrammatic approach.

Abstract

A general scheme to calculate dynamical susceptibilities of strongly correlated electron systems within the dynamical mean field theory is developed. Approach is based on an expansion over electron hopping around the atomic limit (within the diagrammatic technique for site operators: projection and Hubbard ones) in infinite dimensions. As an example, the Falicov-Kimball and simplified pseudospin-electron models are considered for which an analytical expressions for dynamical susceptibilities are obtained.