Symmetry projection to coupled-cluster singles and doubles wave function through the Monte Carlo method

TL;DR

This paper introduces a Monte Carlo-based method for calculating symmetry-projected energies in CCSD wave functions, demonstrating accurate results in a simplified Lipkin model with two phases.

Contribution

It presents a novel Monte Carlo approach for symmetry projection in CCSD wave functions, improving energy calculations in minimal models.

Findings

Accurate ground state energies achieved

Effective in modeling spherical and deformed phases

Demonstrates good low-lying spectra predictions

Abstract

A new method for calculating the symmetry-projected energy of coupled-cluster singles and doubles (CCSD) wave function through the Monte Carlo method is proposed. We present benchmark calculations in considering the three-level Lipkin model which is a simple and minimal model with two phases: spherical and deformed ones. It is demonstrated that this new method gives good ground state energy and low-lying spectra.