A Fast Impurity Solver Based on Gutzwiller variational approach

TL;DR

This paper introduces a rapid impurity solver for DMFT using the Gutzwiller variational approach, capable of directly computing spectral functions at zero temperature and adaptable to multi-orbital systems.

Contribution

The paper presents a novel, fast impurity solver based on Gutzwiller variational method that efficiently handles multi-orbital impurity problems in DMFT.

Findings

Results agree well with Exact Diagonalization on Hubbard models.

The solver captures both coherent and incoherent electron motions.

Works directly on real frequency at zero temperature.

Abstract

A fast impurity solver for the dynamical mean field theory(DMFT) named Two Mode Approxi- mation (TMA) is proposed based on the Gutzwiller variational approach, which captures the main features of both the coherent and incoherent motion of the electrons. The new solver works with real frequency at zero temperature and it provides directly the spectral function of the electrons. It can be easily generalized to multi-orbital impurity problems with general on-site interactions, which makes it very useful in LDA+DMFT. Benchmarks on one and two band Hubbard models are presented, and the results agree well with those of Exact Diagonalization (ED).