Power series expansion method in tensor-optimized antisymmetrized molecular dynamics beyond the Jastrow correlation method

TL;DR

This paper introduces a novel variational method called TOAMD that employs a power series expansion of correlation functions to improve the description of nuclei, outperforming the traditional Jastrow method.

Contribution

The paper presents a new power series expansion approach in TOAMD that independently optimizes correlation functions, enhancing nuclear structure calculations beyond the Jastrow method.

Findings

TOAMD yields better energies for s-shell nuclei than variational Monte Carlo with Jastrow.

The power series expansion effectively describes nuclear correlations.

Independent optimization of correlation functions improves variational results.

Abstract

We developed a new variational method for tensor-optimized antisymmetrized molecular dynamics (TOAMD) for nuclei. In TOAMD, the correlation functions for the tensor force and the short-range repulsion are introduced and used in the power series form of the wave function, which is different from the Jastrow method. Here, nucleon pairs are correlated in multi-steps with different forms, while they are correlated only once including all pairs in the Jastrow correlation method. Each correlation function in every term is independently optimized in the variation of total energy in TOAMD. For $s$-shell nuclei using the nucleon-nucleon interaction, the energies in TOAMD are better than those in the variational Monte Carlo method with the Jastrow correlation function. This means that the power series expansion using the correlation functions in TOAMD describes the nuclei better than the Jastrow correlation method.