Green's Function Formalism for Highly Correlated Systems

TL;DR

This paper introduces the Composite Operator Method (COM), a Green's function-based approach for analyzing strongly correlated electronic systems, emphasizing algebraic constraints to preserve symmetry and algebraic properties.

Contribution

The paper presents COM as a novel, systematic framework that uses composite operators and algebraic constraints to improve the study of highly correlated systems.

Findings

COM effectively maintains algebraic and symmetry properties in calculations

The method provides a structured way to approximate Green's functions

COM offers a new perspective for analyzing strongly correlated electrons

Abstract

We present the Composite Operator Method (COM) as a modern approach to the study of strongly correlated electronic systems, based on the equation of motion and Green's function method. COM uses propagators of composite operators as building blocks at the basis of approximate calculations and algebra constrains to fix the representation of Green's functions in order to maintain the algebraic and symmetry properties.