Pairing in hot rotating nuclei

TL;DR

This paper investigates how nuclear pairing properties are affected by temperature and rotation, revealing that quasiparticle-number fluctuations smooth phase transitions and induce thermally assisted pairing gaps in rotating nuclei.

Contribution

It introduces a formalism incorporating quasiparticle-number fluctuations and vibrational couplings at finite temperature and angular momentum, providing new insights into nuclear pairing behavior.

Findings

QNF smoothes out sharp superfluid-normal phase transition

Thermally assisted pairing gap appears in rotating nuclei

Backbending of moment of inertia is analyzed

Abstract

Nuclear pairing properties are studied within an approach that includes the quasiparticle-number fluctuation (QNF) and coupling to the quasiparticle-pair vibrations at finite temperature and angular momentum. The formalism is developed to describe non-collective rotations about the symmetry axis. The numerical calculations are performed within a doubly-folded equidistant multilevel model as well as several realistic nuclei. The results obtained for the pairing gap, total energy and heat capacity show that the QNF smoothes out the sharp SN phase transition and leads to the appearance of a thermally assisted pairing gap in rotating nuclei at finite temperature. The corrections due to the dynamic coupling to SCQRPA vibrations and particle-number projection are analyzed. The effect of backbending of the momentum of inertia as a function of squared angular velocity is also discussed.