Excitation spectra of exotic nuclei in a self-consistent phonon-coupling model

Lyutorovich, N.; Tselyaev, V.; Speth, J.; Reinhard, P.‐G.

doi:10.1103/physrevc.98.054304

Cited by 14 publications

(5 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another class of models is based on the phonon degrees of freedom [11][12][13][14]. The use of effective phenomenological interactions allows for simpler calculation schemes, however, more accurate and sophisticated versions of the nuclear field theory (NFT) were successfully implemented [15][16][17][18][19][20][21][22][23][24]. Analogous models operating with mostly the phonon degrees of freedom [11][12][13][14], were extended to very complex correlations, and there have been a few recent attempts of using the bare nucleon-nucleon interaction [25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Temperature evolution of the nuclear shell structure and the dynamical nucleon effective mass

Wibowo,

Litvinova,

Zhang

et al. 2020

Preprint

View full text Add to dashboard Cite

We study the fermionic Matsubara Green functions in medium-mass nuclei at finite temperature. The single-fermion Dyson equation with the dynamical kernel of the particle-vibration-coupling (PVC) origin is formulated and solved in the basis of Dirac spinors, which minimize the grand canonical potential with the meson-nucleon covariant energy density functional. The PVC correlations beyond mean field are taken into account in the leading approximation for the energy-dependent selfenergy, and the full solution of the finite-temperature Dyson equation is obtained for the fermionic propagators. Within this approach, we investigate the fragmentation of the single-particle states and its evolution with temperature for the nuclear systems 56,68 Ni and 56 Fe relevant for the corecollapse supernova. The energy-dependent, or dynamical, nucleon effective mass is extracted from the PVC self-energy at various temperatures.

show abstract

Section: Introductionmentioning

confidence: 99%

Temperature evolution of the nuclear shell structure and the dynamical nucleon effective mass

Wibowo,

Litvinova,

Zhang

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…It has been supplemented by the subtraction procedure introduced in analogy with those of quantum electrodynamics, which enables one to avoid double counting of the particlevibration coupling (PVC) in the frameworks based on phenomenological mean fields or effective energy density functionals [60,61]. Since then the time blocking approximation is used consistently in non-relativistic [62][63][64][65][66] and relativistic [51][52][53][54][67][68][69] nuclear structure calculations. The method is systematically improvable and admits extensions which include time-reversed PVC loops as complex ground state correlations [58,59,69] and higher-order configurations [89].…”

Section: Introductionmentioning

confidence: 99%

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

Wibowo

Литвинова

2019

Phys. Rev. C

View full text Add to dashboard Cite

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...

show abstract

“…1: Schematic show of the interaction of Q1HQ2 and Q2HQ2, corresponding to the matrix elements in Eqs. (30,31).…”

Section: A From Hartree-fock To Random Phase Approximationmentioning

confidence: 99%

“…Two main effects were identified to contribute to the width, the escape of a nucleon from the nucleus (escape width) and the spreading of the excitation energy into more complicated configurations (spreading width) [18]. Different efforts have been made to take into account these effects, for example: continuum RPA [19,20]; second RPA (SRPA) [21][22][23][24][25]; quasiparticlephonon model [26][27][28][29] quasiparticle-phonon model based on time-blocking approximation (TBA) [30][31][32]; TBA in the relativistic framework [33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Particle-vibration coupling for giant resonances beyond the diagonal approximation

Shen¹,

Roca-Maza²

2020

Phys. Rev. C

View full text Add to dashboard Cite

A fully self-consistent particle-vibration coupling (PVC) model is presented. The main novelty stands in releasing the so-called diagonal approximation that neglects completely the interaction between the doorway states. As applications, isoscalar giant monopole, dipole, and quadrupole resonances in 16 O are investigated based on the use of Skyrme functionals. The diagonal approximation is found to clearly impact on the strength distribution of the giant quadrupole resonance, and the description of the experimental data is improved when we perform the full calculation. The impact of the diagonal approximation is analyzed in detail, especially its effect on the eigenenergies and the induced coupling between neutron and proton particle-hole configurations. The latter is a direct and physically sound effect of the improvement on our formalism. The importance of using self-consistently the full effective interaction in the PVC vertex, and the effect of its renormalization via the subtraction method are also discussed. For completness, we also analyze the dependence on the Skyrme parameterization in our results.PACS numbers:

show abstract

Excitation spectra of exotic nuclei in a self-consistent phonon-coupling model

Cited by 14 publications

References 64 publications

Temperature evolution of the nuclear shell structure and the dynamical nucleon effective mass

Temperature evolution of the nuclear shell structure and the dynamical nucleon effective mass

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

Particle-vibration coupling for giant resonances beyond the diagonal approximation

Contact Info

Product

Resources

About