Many-body calculations with Deuteron based single-particle bases and their associated natural orbits

TL;DR

This paper introduces a new basis derived from localized Deuteron wave-functions for nuclear many-body calculations, demonstrating significant energy lowering and improved results for various nuclei.

Contribution

The study presents a novel approach using Deuteron-based single-particle states and natural orbitals to enhance nuclear many-body calculations, with practical approximation methods.

Findings

Energy levels are substantially lowered using Deuteron-based natural orbitals.

The energy lowering effect increases with the mass of the nucleus.

Approximate preliminary calculations are sufficient to achieve improvements.

Abstract

We use the recently introduced single-particle states obtained from localized Deuteron wave-functions as a basis for nuclear many-body calculations. We show that energies can be substantially lowered if the natural orbits obtained from this basis are used. We use this modified basis for ${}^{10}B$, ${}^{16}O$ and ${}^{24}Mg$ employing the bare $NNLO_{opt}$ Nucleon-Nucleon interaction. The lowering of the energies increases with the mass. Although in principle natural orbits require a full scale preliminary many-body calculation, we found that an approximate preliminary many-body calculation, with a marginal increase in the computational cost, is sufficient. The use of natural orbits based on an harmonic oscillator basis leads to a much smaller lowering of the energies for a comparable computational cost.