The subtle connection between shape coexistence and quantum phase transition. The Zr case

Abstract

Background: Zr region is characterized by very rapid changes in the ground state structure of the nuclei. In particular, the onset of deformation when passing from ${}^{98}$Zr to ${}^{100}$Zr is one of the fastest ever observed in the nuclear chart. It has been probed both experimental and theoretically that certain low-lying excited states of Zr isotopes own different shapes than the ground state. Purpose: We intend to disentangle the interplay between the sudden changes in the ground state shape, i.e., the existence of a quantum phase transition, and the presence in the spectra of coexisting states with very different deformation, i.e., the presence of shape coexistence. Method: We rely on a previous calculation using the Interacting Boson Model with Configuration Mixing (IBM-CM) which reproduces in detail the spectroscopic properties of ${}^{96-110}$Zr. This IBM-CM calculation allows to compute mean-field energy surfaces, wave functions and any other observable related with the presence of shape coexistence or with a quantum phase transition. Results: We obtain energy surfaces and the equilibrium value of the deformation parameter $\beta$, the U(5) decomposition of the wave functions and the density of states. Conclusions: We confirm that Zr is a clear example of quantum phase transition that originates from the crossing of two configurations with a very different degree of deformation. Moreover, we observe how the intruder configuration exhibits its own evolution which resembles a quantum phase transition too.

Accepted in Physical Review C

References in corpus (24)

• Quantum Phase Transition in the Shape of Zr isotopes
• Quantum phase transitions in the interacting boson model
• Novel shape evolution in exotic Ni isotopes and configuration-dependent shell structure
• Charge radii and structural evolution in Sr, Zr, and Mo isotopes
• First Measurement of Collectivity of Coexisting Shapes based on Type II Shell Evolution: The Case of ${}^{96}$Zr
• Structural evolution in $A\approx 100$ nuclei within the mapped interacting boson model based on the Gogny energy density functional
• Coexistence of spherical states with deformed and superdeformed bands in doubly magic 40-Ca; A shell model challenge
• Nuclear shape coexistence: A study of the even-even Hg isotopes using the interacting boson model with configuration mixing
• Quantum Phase Transitions in the Interacting Boson Model: Integrability, level repulsion and level crossing
• The quest of shape coexistence in Zr isotopes
• Shape evolution and shape coexistence in Pt isotopes: comparing interacting boson model configuration mixing and Gogny mean-field energy surfaces
• The Pt isotopes: comparing the Interacting Boson Model with Configuration Mixing and the Extended Consistent-Q formalism
• Intertwined Quantum Phase Transitions in the Zr Isotopes
• Evidence for coexisting shapes in ${}^{98}$Zr through lifetime measurements
• The platinum nuclei: concealed configuration mixing and shape coexistence
• A theoretical description of energy spectra and two-neutron separation energies for neutron-rich zirconium isotopes
• Nuclear shape coexistence in Po isotopes: An interacting boson model study
• Two-neutron separation energies, binding energies and phase transitions in the interacting boson model
• Interplay between shape-phase transitions and shape coexistence in the Zr isotopes
• Disentangling the nuclear shape coexistence in even-even Hg isotopes using the interacting boson model
• On the nature of the shape coexistence and the quantum phase transition phenomena: lead region and Zr isotopes
• Empirical signatures of shape phase transitions in nuclei with odd nucleon numbers
• B(E2) strength ratio of one-phonon 2+ states of 94Zr from electron scattering at low momentum transfer
• The influence of intruder states in even-even Po isotopes

Cited by in corpus (13)

• Shape coexistence in even-even nuclei: A theoretical overview
• Zr Isotopes as a region of intertwined quantum phase transitions
• Islands of shape coexistence from single-particle spectra in covariant density functional theory
• Signatures for shape coexistence and shape/phase transitions in even-even nuclei
• Microscopic origin of shape coexistence in the N=90, Z=64 region
• Shape coexistence in Sr isotopes
• The nucleon-pair approximation for nuclei from spherical to deformed regions
• Low-energy structure and $\beta$ decay properties of neutron-rich nuclei in the region of a shape phase transition
• Mapped interacting boson model for nuclear structure studies
• Evolution of the phenomenologically determined collective potential along the chain of Zr isotopes
• Single-particle and collective structures in neutron-rich Sr isotopes
• Enlarged deformation region in neutron-rich Zr isotopes by the second intruder orbit
• Shape evolution in even-mass ${}^{98-104}$Zr isotopes via lifetime measurements using the $\gamma \gamma$-coincidence technique