Improved Green's Function Measurement for Hybridization Expansion Quantum Monte Carlo

TL;DR

This paper introduces an improved algorithm for measuring Green's functions in hybridization expansion quantum Monte Carlo simulations, offering better accuracy and reduced noise, especially at low perturbation orders and high frequencies.

Contribution

The proposed algorithm uses continuous estimators to enhance measurement accuracy and reduce noise in Green's function calculations within quantum Monte Carlo methods.

Findings

Improved accuracy at low perturbation orders

Reduced statistical noise in measurements

Enhanced data quality for analytical continuation

Abstract

We present an algorithm for measurement of the Green's function in the hybridization expansion continuous-time quantum Monte-Carlo based on continuous estimators. Compared to the standard method, the present algorithm has similar or better accuracy with improvement notable especially at low perturbation orders and high frequencies. The resulting statistical noise is weakly correlated so high-accuracy data for the numerical analytical continuation can be produced.