Numerically exact Green functions from Hirsch-Fye quantum Monte Carlo simulations

TL;DR

This paper introduces a new technique to accurately extract imaginary-time Green functions from Hirsch-Fye quantum Monte Carlo simulations, enabling bias-free spectral analysis at very low temperatures in strongly correlated systems.

Contribution

The authors develop a method that yields numerically exact Green functions from HF-QMC data, overcoming previous discretization biases in spectral calculations.

Findings

Accurately extracts Green functions at very low temperatures.

Enables bias-free angular resolved spectral analysis.

Demonstrates effectiveness in strongly correlated regimes.

Abstract

We present a new method for extracting numerically exact imaginary-time Green functions from standard Hirsch-Fye quantum Monte Carlo (HF-QMC) simulations within dynamical mean-field theory. By analytic continuation, angular resolved spectra are obtained without the discretization bias previously associated with HF-QMC results. The method is shown to be accurate even at very low temperatures (T=W/800 for bandwidth W) in the strongly correlated regime.