Multipole excitations in hot nuclei within the finite temperature quasiparticle random phase approximation framework

Yüksel, Esra; Colò, G.; Khan, E.; Niu, Y.; Bozkurt, Kutsal

doi:10.1103/physrevc.96.024303

Cited by 28 publications

(52 citation statements)

References 66 publications

(117 reference statements)

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“…The FT-PNQRPA matrices are diagonalized in a self-consistent way, providing a state-by-state analysis for each excitation. The temperature dependencies of the matrices are given by [38,40]…”

Section: Microscopic Model: the Finite Temperature Proton-neutronmentioning

confidence: 99%

“…The detailed information about the other matrices can be found in Ref. [40]. The FT-PNQRPA amplitudes read…”

Section: Microscopic Model: the Finite Temperature Proton-neutronmentioning

confidence: 99%

“…In Fig. 2, the centroid energies (m 1 /m 0 ) [40] and the total sums of the GT − strengths are displayed for the excited states below 10 MeV as a function of tempera- ture. The calculations are performed with the SkM* (left panels) and DD-ME2 (right panels) functionals using different isoscalar pairing strength values in order to gain a better insight into the effects of the interplay between the temperature and isoscalar pairing in the low-energy region.…”

Section: Ca Nucleusmentioning

confidence: 99%

“…The temperature effects on the ground-state properties [31][32][33][34][35][36][37] and excitations [38][39][40][41][42][43][44][45][46][47][48] in nuclei have also been the subject of several studies, not only to understand their properties under extreme conditions, but also in relation to their relevance for astrophysical processes. Long ago, the effect of temperature on the stellar electron capture rates was studied in neutron-rich germanium isotopes using the hybrid model composed of the shell model Monte Carlo (SMMC) approach and the random phase approximation (RPA) [41].…”

Section: Introductionmentioning

confidence: 99%

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Gamow-Teller excitations at finite temperature: Competition between pairing and temperature effects

et al. 2020

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The relativistic and non-relativistic finite temperature proton-neutron quasiparticle random phase approximation (FT-PNQRPA) methods are developed to study the interplay of the pairing and temperature effects on the Gamow-Teller excitations in open-shell nuclei, as well as to explore the model dependence of the results by using two rather different frameworks for effective nuclear interactions. The Skyrme-type functional SkM* is employed in the non-relativistic framework, while the densitydependent meson-exchange interaction DD-ME2 is implemented in the relativistic approach. Both the isoscalar and isovector pairing interactions are taken into account within the FT-PNQRPA. Model calculations show that below the critical temperatures the Gamow-Teller excitations display a sensitivity both to the finite temperature and pairing effects, and this demonstrates the necessity for implementing both in the theoretical framework. The established FT-PNQRPA opens perspectives for the future complete and consistent description of astrophysically relevant weak interaction processes in nuclei at finite temperature such as beta decays, electron capture and neutrino-nucleus reactions.

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Section: Microscopic Model: the Finite Temperature Proton-neutronmentioning

confidence: 99%

“…The detailed information about the other matrices can be found in Ref. [40]. The FT-PNQRPA amplitudes read…”

Section: Microscopic Model: the Finite Temperature Proton-neutronmentioning

confidence: 99%

Section: Ca Nucleusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Gamow-Teller excitations at finite temperature: Competition between pairing and temperature effects

et al. 2020

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“…The right panel of Fig. 8 shows the evolution of the energy-weighted sum rule for 48 Ca and 132 Sn nuclei calculated within FT-RRPA and FT-RTBA in the percentage with respect to the Thomas-Reiche-Kuhn (TRK) sum rule. The EWSR at T > 0 can be calculated in full analogy with the case of T = 0 [38,94].…”

Section: Isovector Dipole Resonance Inmentioning

confidence: 99%

Nuclear dipole response in the finite-temperature relativistic time-blocking approximation

Wibowo

Литвинова

2019

Phys. Rev. C

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Background:The radiative neutron capture reaction rates of the r-process nucleosynthesis are immensely affected by the microscopic structure of the low-energy spectra of compound nuclei. The relativistic (quasiparticle) time blocking approximation (R(Q)TBA) has successfully provided a good description of the lowenergy strength, in particular, the strength associated with pygmy dipole resonance, describing transitions from and to the nuclear ground state. The finite-temperature generalization of this method is designed for thermally excited compound nuclei and has the potential to enrich the fine structure of the dipole strength, especially in the low-energy region. Purpose: To formulate the thermal extension of RTBA, i.e., finite-temperature relativistic time blocking approximation (FT-RTBA) for the nuclear response, and to implement it numerically for calculations of the dipole strength in medium-light and medium-heavy nuclei. Methods: The FT-RTBA equations are derived using the Matsubara Green's function formalism. We show that with the help of a temperature-dependent projection operator on the subspace of the imaginary time it is possible to reduce the Bethe-Salpeter equation for the nuclear response function to a single frequency variable equation also at finite temperatures. The approach is implemented self-consistently in the framework of quantum hadrodynamics and keeps the ability of connecting the high-energy scale of heavy mesons and the low-energy domain of nuclear medium polarization effects in a parameter-free way. Results: The method was applied to the medium-light 48 Ca, 68 Ni and to the medium-heavy 100,120,132 Sn nuclei. The excitation energies E * of the considered compound nuclei were calculated and found to increase quickly starting from temperatures 0.5 ≤ T ≤ 1.0 MeV. The nucleonic single-particle energies and occupancies change accordingly because of the increasing diffuseness of the Fermi-Dirac distribution with the temperature increase. The dipole response of these nuclei was computed in the FT-RTBA and compared to the finite-temperature relativistic RPA (FT-RRPA). It was found that the giant dipole resonance (GDR) undergoes additional fragmentation (i) due to the thermal unblocking of the transitions between single-particle states located on the same side of the Fermi surface and (ii) because of the general reinforcement of the particle-vibration coupling (PVC) with the temperature growth. The low-energy part of the dipole strength distribution is moderately enhanced at temperatures T ≤ 4.0 MeV and increases dramatically above this temperature range. The width of the strength distribution grows rapidly with temperature at T ≥ 1.0 MeV. The energy-weighted sum rule (EWSR) in a wide finite energy interval remains nearly flat as the temperature increases. The traditional view of the PDR as an oscillation of the weakly bound neutron excess against the isospin-saturated core is nearly maintained up to the temperature T = 5.0 MeV and changes to the GDR-like pattern above this temperature. The col...

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Temperature dependence of nuclear properties: A systematic study along the isotopic and isotonic chains of nuclei

Yüksel

2021

Nuclear Physics A

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Multipole excitations in hot nuclei within the finite temperature quasiparticle random phase approximation framework

Cited by 28 publications

References 66 publications

Gamow-Teller excitations at finite temperature: Competition between pairing and temperature effects

Gamow-Teller excitations at finite temperature: Competition between pairing and temperature effects

Nuclear dipole response in the finite-temperature relativistic time-blocking approximation

Temperature dependence of nuclear properties: A systematic study along the isotopic and isotonic chains of nuclei

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