Variational multiparticle-multihole configuration mixing method applied to pairing correlations in nuclei

TL;DR

This paper introduces a variational multiparticle-multihole configuration mixing method to accurately include correlations beyond the mean field in nuclear structure calculations, applied to pairing correlations in specific tin isotopes.

Contribution

The study develops and applies a novel variational method that incorporates correlations beyond mean field without violating particle number or Pauli principle, improving nuclear structure modeling.

Findings

Correlated wave functions show convergence with particle-hole excitations.

Correlation effects influence single-particle spectra and occupation probabilities.

Calculated nuclear radii and excited states agree with experimental data.

Abstract

Applying a variational multiparticle-multihole configuration mixing method whose purpose is to include correlations beyond the mean field in a unified way without particle number and Pauli principle violations, we investigate pairing-like correlations in the ground states of $ ^{116}$Sn,$ ^{106}$Sn and $ ^{100}$Sn. The same effective nucleon-nucleon interaction namely, the D1S parameterization of the Gogny force is used to derive both the mean field and correlation components of nuclear wave functions. Calculations are performed using an axially symetric representation. The structure of correlated wave functions, their convergence with respect to the number of particle-hole excitations and the influence of correlations on single-particle level spectra and occupation probabilities are analyzed and compared with results obtained with the same two-body effective interaction from BCS, Hartree-Fock-Bogoliubov and particle number projected after variation BCS approaches. Calculations of nuclear radii and the first theoretical excited $0^+$ states are compared with experimental data.