Pairing within the self-consistent quasiparticle random-phase approximation at finite temperature

Abstract

An approach to pairing in finite nuclei at nonzero temperature is proposed, which incorporates the effects due to the quasiparticle-number fluctuation (QNF) around Bardeen-Cooper-Schrieffer (BCS) mean field and dynamic coupling to quasiparticle-pair vibrations within the self-consistent quasiparticle random-phase approximation (SCQRPA). The numerical calculations of pairing gap, total energy, and heat capacity were carried out within a doubly folded multilevel model as well as realistic nuclei ${}^{56}$Fe and ${}^{120}$Sn. The results obtained show that, under the effect of QNF, in the region of moderate and strong couplings, the sharp transition between the superconducting and normal phases is smoothed out, resulting in a thermal pairing gap, which does not collapse at the BCS critical temperature, but has a tail, which extends to high temperature. The dynamic coupling of quasiparticles to SCQRPA vibrations significantly improves the agreement with the results of exact calculations and those obtained within the finite-temperature quantal Monte Carlo method for the total energy and heat capacity. It also causes a deviation of the quasiparticle occupation numbers from the Fermi-Dirac distributions for free fermions.

31 pages, 6 figures. Some missing fonts are corrected. Accepted in Phys. Rev. C

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Cited by in corpus (11)

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• Pairing reentrance in hot rotating nuclei
• Pairing in hot rotating nuclei
• Shear-Viscosity to Entropy-Density Ratio from Giant Dipole Resonances in Hot Nuclei
• Canonical and microcanonical ensemble descriptions of thermal pairing within BCS and quasiparticle RPA
• Anti-bubble effect of temperature \& deformation: a systematic study for nuclei across all mass regions between A $=$ 20$-$300
• Thermodynamic properties of hot nuclei within the self-consistent quasiparticle random-phase approximation
• Giant dipole resonance in ${}^{201}$Tl at low temperature
• Improved treatment of blocking effect at finite temperature
• Specific shear viscosity in hot rotating systems of paired fermions
• Thermal nuclear pairing within the self-consistent quasiparticle RPA