Formation of superconducting pair correlations in spherical even-even nuclei

TL;DR

This paper investigates how superconducting-like pair correlations form in spherical even-even nuclei, showing they emerge above a certain interaction strength and are present at all positive coupling constants in open subshells.

Contribution

It introduces a Bogoliubov transformation approach to analyze nucleon pair correlations and estimates the threshold for their formation in closed subshell nuclei.

Findings

Pair correlations form when the coupling constant exceeds a threshold in closed subshells.

Superconducting correlations exist at any positive coupling in open subshells.

Nucleon pairs distribute over all active subshells in open-shell nuclei.

Abstract

The appearance of like nucleon pair correlations in the ground state of spherical even-even nuclei is considered within a special Bogoliubov transformation. It is confirmed that in closed subshell nuclei superconducting pair correlations start to form if the coupling constant $G$ exceeds a certain threshold value. Rough upper and lower estimates are obtained for the threshold value. It is shown, that superconducting correlations exist in open subshell nuclei at any positive $G$. In this case, nucleon pairs are distributed over all subshells participating in the pairing interaction.