Imaginary chemical potential quantum Monte Carlo for Hubbard molecules

TL;DR

This paper extends the imaginary chemical potential quantum Monte Carlo method to systems lacking particle-hole symmetry, validating it on small Hubbard molecules and applying it to the C60 molecule.

Contribution

The paper introduces a generalized QMC method for non-particle-hole symmetric systems and demonstrates its effectiveness through comparison with exact solutions.

Findings

QMC results agree with exact diagonalization on small molecules

Method successfully applied to C60 Hubbard molecule

Provides a new tool for studying complex Hubbard systems

Abstract

We generalize the imaginary chemical potential quantum Monte Carlo (QMC) method proposed by Dagotto et al. [Phys. Rev. B 41, R811 (1990)] to systems without particle-hole symmetry. The generalized method is tested by comparing the results of the QMC simulations and exact diagonalization on small Hubbard molecules, such as tetrahedron and truncated tetrahedron. Results of the application of the method to the C$_{60}$ Hubbard molecule are discussed.