Continuous-Time Quantum Monte Carlo Algorithm for the Lattice Polaron

TL;DR

This paper introduces a continuous-time Quantum Monte Carlo algorithm for lattice polarons that accurately computes ground-state properties and spectra without finite-size or time-step errors, applicable across various models and dimensions.

Contribution

It presents a novel, efficient continuous-time path-integral Monte Carlo method for lattice polarons, eliminating finite-size and finite-time-step errors and applicable to any dimensionality and interaction range.

Findings

Accurate calculation of polaron ground-state energy and effective mass.

Direct measurement of polaron spectrum via Monte Carlo.

Method applicable to various models and dimensions.

Abstract

An efficient continuous-time path-integral Quantum Monte Carlo algorithm for the lattice polaron is presented. It is based on Feynman's integration of phonons and subsequent simulation of the resulting single-particle self-interacting system. The method is free from the finite-size and finite-time-step errors and works in any dimensionality and for any range of electron-phonon interaction. The ground-state energy and effective mass of the polaron are calculated for several models. The polaron spectrum can be measured directly by Monte Carlo, which is of general interest.