Localization of pairing correlations in nuclei within relativistic mean field models

TL;DR

This paper investigates how pairing correlations are localized within nuclei using relativistic mean field models, comparing different approaches and analyzing how pairing strength influences coherence length.

Contribution

It introduces a detailed analysis of two-body correlation localization in nuclei within RMF models, including the impact of pairing force strength on coherence length.

Findings

Coherence length peaks inside the nucleus and decreases towards the surface.

Pairing reduces the coherence length by approximately 25-30%.

Similar localization patterns are observed as in non-relativistic calculations.

Abstract

We analyze the localization properties of two-body correlations induced by pairing in the framework of relativistic mean field (RMF) models. The spatial properties of two-body correlations are studied for the pairing tensor in coordinate space and for the Cooper pair wave function. The calculations are performed both with Relativistic-Hatree-Bogoliubov (RHB) and RMF+Projected-BCS (PBCS) models and taking as examples the nuclei $^{66}$Ni, $^{124}$Sn and $^{200}$Pb. It is shown that the coherence length have the same pattern as in previous non-relativistic HFB calculations, i.e., it is maximum in the interior of the nucleus and drops to a minimum in the surface region. In the framework of RMF+PBCS we have also analysed, for the particular case of $^{120}$Sn, the dependence of the coherence length on the intensity of the pairing force. This analysis indicates that pairing is reducing the coherence length by about 25-30 $\%$ compared to the RMF limit.