Quadrupole Collective Dynamics from Energy Density Functionals: Collective Hamiltonian and the Interacting Boson Model

TL;DR

This paper compares two models, the collective Hamiltonian and the Interacting Boson Model, for describing quadrupole collective dynamics in nuclei, using energy density functionals to analyze shape evolution in Pt isotopes.

Contribution

It provides a detailed comparison of the collective Hamiltonian and IBM-2 approaches based on microscopic energy density functional calculations for nuclear shape dynamics.

Findings

Good agreement with experimental spectra for ground-state bands

Both models effectively describe shape evolution in Pt isotopes

Transition probabilities match observed data

Abstract

Microscopic energy density functionals (EDF) have become a standard tool for nuclear structure calculations, providing an accurate global description of nuclear ground states and collective excitations. For spectroscopic applications this framework has to be extended to account for collective correlations related to restoration of symmetries broken by the static mean field, and for fluctuations of collective variables. In this work we compare two approaches to five-dimensional quadrupole dynamics: the collective Hamiltonian for quadrupole vibrations and rotations, and the Interacting Boson Model. The two models are compared in a study of the evolution of non-axial shapes in Pt isotopes. Starting from the binding energy surfaces of $^{192,194,196}$Pt, calculated with a microscopic energy density functional, we analyze the resulting low-energy collective spectra obtained from the collective Hamiltonian, and the corresponding IBM-2 Hamiltonian. The calculated excitation spectra and transition probabilities for the ground-state bands and the $\gamma$-vibration bands are compared to the corresponding sequences of experimental states.