A semiclassical collective response of heated, asymmetric and rotating nuclei

TL;DR

This paper develops a semiclassical framework combining Fermi-liquid and periodic-orbit theories to describe collective excitations in heated, asymmetric, and rotating nuclei, aligning well with experimental data and advancing nuclear response understanding.

Contribution

It introduces a semiclassical approach integrating Fermi-liquid and periodic-orbit theories for nuclei, providing new insights into collective excitations, moments of inertia, and resonance structures.

Findings

Transport coefficients depend on temperature and agree with shell model predictions.

Surface symmetry energy constants are derived from Skyrme force parameters.

Good agreement between semiclassical and quantum shell-structure components of moment of inertia.

Abstract

The Landau Fermi-liquid and extended Gutzwiller periodic-orbit theories are presented for the semiclassical description of collective excitations in nuclei, which are close to main topics of the fruitful activity of S.T. Belyaev. Static susceptibilities show the ergodicity of Fermi liquids. Transport coefficients (nuclear friction and inertia) as functions of the temperature for the hydrodynamic and zero-sound modes are derived within the response theory by using the Fermi-liquid droplet model, in agreement with the shell model for large temperatures. The surface symmetry binding-energy constants are obtained as functions of Skyrme force parameters in the approximation of a sharp edged proton-neutron asymmetric nucleus.The energies and sum rules of the isovector dipole giant resonances are in fairly good agreement with the experimental data. An analysis of the specific structure of these resonances in terms of a main, and satellite peaks, in comparison with the experimental data and microscopic theoretical models, might turn out to be of importance for a better understanding of the values of the surface symmetry-energy constant. The semiclassical collective moment of inertia is derived analytically beyond the quantum perturbation approximation of the cranking model for any potential well as a mean field. It is shown that this moment of inertia can be approximated by its rigid-body value for the rotation with a given frequency within the ETF and more general periodic orbit theories in the nearly local long-length approximation. Its semiclassical shell-structure components are derived in terms of the periodic-orbit free-energy shell corrections. We obtained good agreement between the semiclassical and quantum shell-structure components of the moment of inertia for several critical bifurcation deformations for the harmonic oscillator mean field.