Importance of the single-particle continuum in BCS pairing with a pseudostate basis

J A Lay,C E Alonso,L Fortunato,A Vitturi

doi:10.1051/epjconf/201611706018

Abstract

In a recent work [arXiv:1510.03185] the use of the Transformed Harmonic Oscillator (THO) basis for the discretization of the singleparticle continuum into a Generalized Bardeen-Cooper-Schrieffer (BCS) formalism was proposed for the description of weakly bound nuclei. We make use of the flexibility of this formalism to study the evolution of the pairing when the nucleus becomes more and more weakly bound. Specifically we focus on the evolution of the occupation of the different partial waves in 22 O when the Fermi level approaches zero.

Highlights

The effects of the continuum have been traditionally explored for light nuclei where the proximity of the driplines provides a rich variety of weakly bound nuclei and experimental data
The pseudostates or eigenstates obtained through the diagonalization of the matrix elements of the single-particle Hamiltonian are expected to give a good representation of the continuum
The strength of the pairing is determined by a densitydependent delta interaction and matrix elements are calculated separately for each couple of pairs

Summary

Introduction

The effects of the continuum have been traditionally explored for light nuclei where the proximity of the driplines provides a rich variety of weakly bound nuclei and experimental data. In order to do so, the single-particle continuum is discretized using a square-integrable basis. Already in [3], an interesting increase of the occupation of the nonresonant low-energy continuum was found for extremely weakly bound situations.

Results

Conclusion