Directed update for the Stochastic Green Function algorithm

TL;DR

This paper introduces a modified update scheme for the stochastic Green function (SGF) algorithm, maintaining its simplicity and broad applicability while significantly improving its efficiency for lattice Hamiltonians of a specific form.

Contribution

A new version of the SGF algorithm's update scheme that enhances efficiency without sacrificing its generality or simplicity.

Findings

Enhanced efficiency of the SGF algorithm.

Maintains generality for lattice Hamiltonians of the form H=V-T.

Simplifies application to various models.

Abstract

In a recent publication (Phys. Rev E 77, 056705 (2008)),we have presented the stochastic Green function (SGF) algorithm, which has the properties of being general and easy to apply to any lattice Hamiltonian of the form H=V-T, where V is diagonal in the chosen occupation number basis and T has only positive matrix elements. We propose here a modified version of the update scheme that keeps the simplicity and generality of the original SGF algorithm, and enhances significantly its efficiency.