Equation-of-Motion Approach to Dynamical Mean Field Theory

TL;DR

This paper introduces an equation-of-motion method as a new impurity solver for dynamical mean field theory, demonstrating its effectiveness on the Hubbard model and comparing favorably with exact solutions.

Contribution

It presents a novel equation-of-motion approach for impurity solving in dynamical mean field theory, offering an alternative to existing methods.

Findings

Accurately reproduces spectral features like quasiparticle peaks and Hubbard bands.

Shows good agreement with exact diagonalization results.

Provides a different perspective on spectral weight transfer compared to iterative perturbation theory.

Abstract

We propose using an equation-of-motion approach as an impurity solver for dynamical mean field theory. As an illustration of this technique, we consider a finite-$U$ Hubbard model defined on the Bethe lattice with infinite connectivity at arbitrary filling. Depending on the filling, the spectra that is obtained exhibits a quasiparticle peak, and lower and upper Hubbard bands as typical features of strongly correlated materials. The results are also compared and in good agreement with exact diagonalization. We also find a different picture of the spectral weight transfer than the iterative perturbation theory.