The effect of temperature on the evolution of the isovector dipole and isoscalar quadrupole excitations in 68 Ni and 120 Sn nuclei is studied within the fully self-consistent finite temperature quasiparticle random phase approximation framework, based on the Skyrme-type SLy5 energy density functional. The new low-energy excitations emerge due to the transitions from thermally occupied states to the discretized continuum at finite temperatures, whereas the isovector giant dipole resonance is not strongly impacted by the increase of temperature. The radiative dipole strength at low energies is also investigated for the 122 Sn nucleus, becoming compatible with the available experimental data when the temperature is included. In addition, both the isoscalar giant quadrupole resonance and low-energy quadrupole states are sensitive to the temperature effect: while the centroid energies decrease in the case of the isoscalar giant quadrupole resonance, the collectivity of the first 2 + state is quenched and the opening of new excitation channels fragments the low-energy strength at finite temperatures.

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We study the finite temperature Hartree-Fock-BCS approximation for selected stable Sn nuclei with zero-range Skyrme forces. Hartree Fock BCS approximation allows for a straightforward interpretation of the results since it involves u and v's which are not matrices as in HFB. Pairing transitions from superfluid to the normal state are studied with respect to the temperature. The temperature dependence of the nuclear radii and neutron skin are also analyzed. An increase of proton and neutron radii is obtained in neutron rich nuclei especially above the critical temperature. Using different Skyrme energy functionals, it is found that the correlation between the effective mass in symmetric nuclear matter and the critical temperature depends on the pairing prescription. The temperature dependence of the nucleon effective mass is also investigated, showing that proton and neutron effective masses display different behavior below and above the critical temperature, due to the small temperature dependence of the density.

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The magic nature of the 54 Ca nucleus is investigated in the light of the recent experimental results. We employ both HFB and HF+BCS methods using Skyrme-type SLy5, SLy5+T and T44 interactions. The evolution of the single-particle spectra is studied for the N=34 isotones: 60 Fe, 58 Cr, 56 Ti and 54 Ca. An increase is obtained in the neutron spinorbit splittings of p and f states due to the effect of the tensor force which also makes 54 Ca a magic nucleus candidate. QRPA calculations on top of HF+BCS are performed to investigate the first J π =2 + states of the calcium isotopic chain. A good agreement for excitation energies is obtained when we include the tensor force in the mean-field part of the calculations. The first 2 + states indicate a subshell closure for both 52 Ca and 54 Ca nuclei. We confirm that the tensor part of the interaction is quite essential in explaining the neutron subshell closure in 52 Ca and 54 Ca nuclei.

Multi-strange Ca, Sn and Pb hypernuclei with ΛΛ pairing interaction are investigated within the Hartree-Fock-Bogoliubov approach. The unknown ΛΛ pairing strength is calibrated to match with the maximal value for the prediction of the Λ pairing gap in uniform matter for densities and isospin asymmetries equivalent to those existing in multi-Λ hypernuclei. In this way, we provide an upper bound for the prediction of the Λ pairing gap and its effects in hypernuclei. The condensation energy is predicted to be about 3 MeV as a maximum value, yielding small corrections on density distributions and shell structure. In addition, conditions on both Fermi energies and orbital angular momenta are expected to quench the nucleon-Λ pairing for most of hypernuclei.

We investigate tensor effects in pygmy dipole excitations for the case of neutron-rich nuclei 68 Ni and 124 Sn using effective nucleon–nucleon Skyrme interaction. We use the Hartree–Fock–Bogoliubov (HFB) theory and employ the quasiparticle random phase approximation (QRPA). We calculate and compare the PDR and also GDR strength in the PDR–GDR energy region for QRPA calculations with and without tensor correlations. The most obvious results for the dipole excitations calculations are strongly dependent on the tensor terms. We see that the tensor correlations are more active at around 14–20 MeV , especially for the neutron-rich nuclei 68 Ni . We also compare the PDR calculations with their experimental results for the different proton–neutron tensor coupling constants.

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