Study of pygmy dipole resonance with a new time-dependent mean field theory

TL;DR

This paper introduces a new time-dependent mean field method, Cb-TDHFB, to systematically study pygmy dipole resonances in nuclei, revealing neutron-number dependence in PDR strength across isotopes.

Contribution

The paper presents the canonical-basis time-dependent Hartree-Fock-Bogoliubov (Cb-TDHFB) method, a novel approach derived from TDHFB with BCS-like approximation, for analyzing low-energy dipole excitations.

Findings

Neutron-number dependence of PDR in light and heavy isotopes

Application of Cb-TDHFB to linear-response calculations

Observation of PDR characteristics around N=82

Abstract

We carry out a systematic investigation on the low-energy electric dipole strength, which is often called pygmy dipole resonances (PDR), using the canonical-basis time-dependent Hartree-Fock-Bogoliubov (Cb-TDHFB) method. The Cb-TDHFB is a new method which is derived from TDHFB with an approximation analogous to the BCS theory that the pair potential is assumed to be diagonal in the time-dependent canonical basis. We apply the method to linear-response calculation for even-even nuclei. We report the neutron-number dependence of PDR in light (A < 70) and heavy isotopes (A > 100) around N = 82.