Five-dimensional collective Hamiltonian with improved inertial functions

Fuente: arXiv
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Main Authors: Washiyama, Kouhei, Hinohara, Nobuo, Nakatsukasa, Takashi
Format: Preprint
Published: 2024
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_version_ 1866909223824130048
author Washiyama, Kouhei
Hinohara, Nobuo
Nakatsukasa, Takashi
author_facet Washiyama, Kouhei
Hinohara, Nobuo
Nakatsukasa, Takashi
contents Background: To describe shape fluctuations associated with large-amplitude collective motion in the quadrupole degrees of freedom, the five-dimensional collective Hamiltonian (5DCH) has been widely used. The inertial functions in the 5DCH are microscopically calculated with the energy density functional (EDF) theory employing the cranking formula. However, since the cranking formula ignores dynamical residual effects, it is known to fail to reproduce the correct inertial functions, for instance, the total mass for the translational motion. Purpose: We aim to resolve problems of the insufficient description of the inertial functions in the 5DCH. We provide a practical method to include the dynamical residual effects in the inertial functions that depend on the quadrupole deformation parameters $β$ and $γ$. Methods: We use the local quasiparticle random-phase approximation (LQRPA) based on the constrained Hartree-Fock-Bogoliubov states in the $β$--$γ$ plane with the Skyrme EDF. The finite-amplitude method is used for efficient computations of the LQRPA. Results: The inertial functions evaluated with the LQRPA significantly increase from the ones with the cranking formula due to the dynamical residual effects. This increase also shows a strong $β$--$γ$ dependence. We show an application of the present method to a transitional nucleus $^{110}$Pd. The low-lying positive-parity spectra are well reproduced with the LQRPA inertial functions. Conclusions: We clarify the importance of the dynamical residual effects in the inertial functions of the 5DCH for the description of the low-lying spectra. The 5DCH with the improved inertial functions provides a reliable and efficient description of low-lying spectra in nuclei associated with the quadrupole shape fluctuation.
format Preprint
id arxiv_https___arxiv_org_abs_2403_00214
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Five-dimensional collective Hamiltonian with improved inertial functions
Washiyama, Kouhei
Hinohara, Nobuo
Nakatsukasa, Takashi
Nuclear Theory
Nuclear Experiment
Background: To describe shape fluctuations associated with large-amplitude collective motion in the quadrupole degrees of freedom, the five-dimensional collective Hamiltonian (5DCH) has been widely used. The inertial functions in the 5DCH are microscopically calculated with the energy density functional (EDF) theory employing the cranking formula. However, since the cranking formula ignores dynamical residual effects, it is known to fail to reproduce the correct inertial functions, for instance, the total mass for the translational motion. Purpose: We aim to resolve problems of the insufficient description of the inertial functions in the 5DCH. We provide a practical method to include the dynamical residual effects in the inertial functions that depend on the quadrupole deformation parameters $β$ and $γ$. Methods: We use the local quasiparticle random-phase approximation (LQRPA) based on the constrained Hartree-Fock-Bogoliubov states in the $β$--$γ$ plane with the Skyrme EDF. The finite-amplitude method is used for efficient computations of the LQRPA. Results: The inertial functions evaluated with the LQRPA significantly increase from the ones with the cranking formula due to the dynamical residual effects. This increase also shows a strong $β$--$γ$ dependence. We show an application of the present method to a transitional nucleus $^{110}$Pd. The low-lying positive-parity spectra are well reproduced with the LQRPA inertial functions. Conclusions: We clarify the importance of the dynamical residual effects in the inertial functions of the 5DCH for the description of the low-lying spectra. The 5DCH with the improved inertial functions provides a reliable and efficient description of low-lying spectra in nuclei associated with the quadrupole shape fluctuation.
title Five-dimensional collective Hamiltonian with improved inertial functions
topic Nuclear Theory
Nuclear Experiment
url https://arxiv.org/abs/2403.00214