Optimization of Gutzwiller Wavefunctions in Quantum Monte Carlo

TL;DR

This paper presents an efficient method for optimizing Gutzwiller wavefunctions in quantum Monte Carlo simulations, improving the accuracy of modeling correlated electron systems in Hubbard models.

Contribution

It introduces a novel approach to minimize the Gutzwiller wavefunction parameters by rewriting the expectation value as a rational function, applicable in variational and fixed-node diffusion Monte Carlo.

Findings

Efficient minimization of Gutzwiller parameters achieved.

Applicable to both variational and fixed-node diffusion Monte Carlo.

Enhances the accuracy of correlated electron simulations.

Abstract

Gutzwiller functions are popular variational wavefunctions for correlated electrons in Hubbard models. Following the variational principle, we are interested in the Gutzwiller parameters that minimize e.g. the expectation value of the energy. Rewriting the expectation value as a rational function in the Gutzwiller parameters, we find a very efficient way for performing that minimization. The method can be used to optimize general Gutzwiller-type wavefunctions both, in variational and in fixed-node diffusion Monte Carlo.