On the nature of the shape coexistence and the quantum phase transition phenomena: lead region and Zr isotopes

José-Enrique García-Ramos,Kris Heyde,Yang Sun

doi:10.1051/epjconf/201817805005

Abstract

The goal of this contribution is to analyze the connection between shape coexistence and quantum phase transition, two seemingly unrelated phenomena that share common aspects, namely, the rapid change in the ground state structure along an isotope chain or the presence of several minima at the mean-field level. To illustrate the similarities and differences between both phenomena, we will focus in the Pb region, in particular in Pt and Hg isotopes, as well as in Zr isotopes.

Highlights

The atomic nuclei can present different shapes, namely, spherical, axially deformed, either prolate or oblate, or even triaxial
We have analyzed the interplay between shape coexistence and quantum phase transition (QPT) in three chain of isotopes, namely Zr, Pt, and Hg, that seem to be the most promising candidates to disentangle the relationship between both phenomena
In the case of Zr, the QPT that appears around A = 100 is explained in terms of the existence of two families of states that cross at the phase transition point

Summary

Introduction

The atomic nuclei can present different shapes, namely, spherical, axially deformed, either prolate or oblate, or even triaxial. The shape evolves in a gradual way as one passes from a nucleus to its neighbor, but in certain cases the change can be very abrupt This is the key element for the appearance of a quantum phase transition (QPT) [1]. The presence of extra configurations can be singled out in the very conspicuous parabolic behaviour in the energy systematics centered around the mid-shell Another relevant indicator of the presence of intruder configurations is the lowering of the first excited 0+ state that presents a minimum around the mid-shell. Along this contribution we try to disentangle which are the relationships and differences between both phenomena. We analyze three different chains of nuclei, Pt, Hg, and Zr which are ideal cases to see the competition between QPT and shape coexistence phenomena

Shape coexistence and quantum phase transition in a nutshell

Conclusions