Shape fluctuations in the ground and excited 0+ states of 30Mg and 32Mg

TL;DR

This study models shape fluctuations in magnesium isotopes 30Mg and 32Mg using a 5D collective Hamiltonian, revealing complex shape coexistence and fluctuations that align well with experimental data.

Contribution

It introduces a microscopic approach to analyze shape phase transitions and fluctuations in magnesium isotopes using the 5D collective Schroedinger equation.

Findings

Good agreement with experimental data for excited 0+ states

Shape coexistence in 30Mg with spherical and deformed states

Large shape fluctuations dominate in 32Mg, challenging simple coexistence interpretation

Abstract

Large-amplitude collective dynamics of shape phase transition in the low-lying states of 30-36Mg is investigated by solving the five-dimensional (5D) quadrupole collective Schroedinger equation. The collective masses and potentials of the 5D collective Hamiltonian are microscopically derived with use of the constrained Hartree-Fock-Bogoliubov plus local quasiparticle RPA method. Good agreement with the recent experimental data is obtained for the excited 0+ states as well as the ground bands. For 30Mg, the shape coexistence picture that the deformed excited 0+ state coexists with the spherical ground state approximately holds. On the other hand, large-amplitude quadrupole-shape fluctuations dominate in both the ground and the excited 0+ states in 32Mg, so that the interpretation of 'coexisting spherical excited 0+ state' based on the naive inversion picture of the spherical and deformed configurations does not hold.