Quantum Monte Carlo simulation in the canonical ensemble at finite temperature

TL;DR

This paper introduces a quantum Monte Carlo method with a non-local update scheme for finite-temperature simulations, capable of efficiently handling fixed particle number states and applicable to models like Bose-Hubbard and nuclear pairing.

Contribution

The paper presents a novel quantum Monte Carlo approach using a path-integral decomposition and worm operator, improving efficiency and symmetry preservation in finite-temperature simulations.

Findings

Efficient evaluation of Green's functions.

Successful application to Bose-Hubbard and nuclear pairing models.

Discussion of algorithm efficiency in the Bose-Hubbard model.

Abstract

A quantum Monte Carlo method with non-local update scheme is presented. The method is based on a path-integral decomposition and a worm operator which is local in imaginary time. It generates states with a fixed number of particles and respects other exact symmetries. Observables like the equal-time Green's function can be evaluated in an efficient way. To demonstrate the versatility of the method, results for the one-dimensional Bose-Hubbard model and a nuclear pairing model are presented. Within the context of the Bose-Hubbard model the efficiency of the algorithm is discussed.