Finite temperature pairing re-entrance in drip-line $^{48}$Ni nucleus

Abstract

Finite-temperature Hartree-Fock-Bogoliubov theory using Skyrme interactions and Relativistic Hartree-Fock effective Lagrangians, predicts $^{48}$Ni as being a possible candidate for the finite temperature pairing re-entrance phenomenon. For this proton-drip-line nucleus, proton resonant states are expected to contribute substantially to pairing correlations and the two predicted critical temperatures are $T_{c1}\sim 0.08-0.2$~MeV and $T_{c2}\sim 0.7-0.9$~MeV. It is also shown that pairing re-entrance modifies the proton single particle energies around the Fermi level, as well as occupation numbers, and quasi-particle levels. The understanding of pairing re-entrance in $^{48}$Ni presently challenge our understanding of exotic matter under extreme conditions.