A simple method to compute excitation energies in variational many-body calculations

TL;DR

The paper introduces a straightforward variant of the EXCITED method for variational many-body calculations, demonstrating its effectiveness in accurately computing excitation energies with few Slater determinants.

Contribution

It presents a new, simple, and easy-to-implement method for calculating excited states in variational many-body approaches, validated on the shell model for nickel-56.

Findings

Achieves very good agreement with exact shell model results.

Requires relatively few Slater determinants for accurate excitation energies.

Applicable to the Hybrid Multideterminant method.

Abstract

We propose a simple, easy to implement, variant of the EXCITED method for variational many-body calculations for excited states. We apply this method to the Hybrid Multideterminant method(HMD). We test this method with relatively few Slater determinants by comparing the results with exact shell model calculations for ${}^{56}Ni$ using the $fpd6$ interaction. We obtain very good agreement with the exact results.