Off-diagonal Wave Function Monte Carlo Studies of Hubbard Model I

TL;DR

This paper introduces a hybrid Monte Carlo method combining quantum and variational techniques to study the Hubbard model, accurately reproducing exact results for small systems and providing reliable energy estimates for larger lattices.

Contribution

A novel Monte Carlo approach integrating off-diagonal and Gutzwiller correlation factors for improved Hubbard model simulations.

Findings

Successfully reproduces exact results for 4x4 systems

Provides energy estimates comparable to quantum Monte Carlo data

Effective for studying half-filled 2D square lattice Hubbard model

Abstract

We propose a Monte Carlo method, which is a hybrid method of the quantum Monte Carlo method and variational Monte Carlo theory, to study the Hubbard model. The theory is based on the off-diagonal and the Gutzwiller type correlation factors which are taken into account by a Monte Carlo algorithm. In the 4x4 system our method is able to reproduce the exact results obtained by the diagonalization. An application is given to investigate the half-filled band case of two-dimensional square lattice. The energy is favorably compared with quantum Monte Carlo data.