Thermal nuclear pairing within the self-consistent quasiparticle RPA

TL;DR

This paper develops a self-consistent quasiparticle RPA method incorporating particle-number projection to analyze finite-temperature nuclear pairing, addressing phase transition smoothing and thermally assisted pairing in rotating nuclei.

Contribution

It introduces a novel PNP SCQRPA approach embedded in statistical ensembles, enhancing the understanding of nuclear pairing at finite temperature and angular momentum.

Findings

Smoothing of superfluid-normal phase transition observed.

Thermally assisted pairing effects identified in hot rotating nuclei.

Improved extraction of nuclear pairing gaps using the method.

Abstract

The self-consistent quasiparticle RPA (SCQRPA) is constructed to study the effects of fluctuations on pairing properties in nuclei at finite temperature and z-projection M of angular momentum. Particle-number projection (PNP) is taken into account within the Lipkin-Nogami method. Several issues such as the smoothing of superfluid-normal phase transition, thermally assisted pairing in hot rotating nuclei, extraction of the nuclear pairing gap using an improved odd-even mass difference are discussed. A novel approach of embedding the PNP SCQRPA eigenvalues in the canonical and microcanonical ensembles is proposed and applied to describe the recent empirical thermodynamic quantities for iron, molybdenum, dysprosium, and ytterbium isotopes.