Self-consistent treatment of dynamical correlation functions using a spectral representation technique

TL;DR

This paper introduces a real-frequency axis method for solving Green function equations in correlated electron systems, demonstrating its effectiveness through the attractive Hubbard model in the T-matrix approximation.

Contribution

It presents a novel real-frequency spectral representation technique for self-consistent calculation of dynamical correlation functions, avoiding Matsubara frequency complexities.

Findings

Effective real-frequency method demonstrated on Hubbard model

Improved calculation of dynamic quantities in correlated systems

Method applicable to self-consistent and non-self-consistent approaches

Abstract

A system of equations resulting from an approximation of the equation of motion of Green functions for correlated electron systems is usually solved using Matsubara technique. In this work we propose an alternative method which works entirely along the real frequency axis. Using the example of the attractive Hubbard model studied in the T-matrix approximation both self-consistently and non-self-consistently we demonstrate how powerful such a treatment is especially when dynamic quantities are calculated.