Ab initio nuclear shape coexistence and emergence of island of inversion around $N=20$

Abstract

We extend a nuclear ab initio framework based on chiral two- and three-nucleon interactions to investigate shape coexistence and the degradation of the $N=20$ magic number in both even-even and odd-even magnesium isotopes. The quantum-number projected generator coordinate method, combined with the in-medium similarity renormalization group (IMSRG), is employed to compute their low-lying states. This approach reasonably reproduces the coexistence of weakly and strongly deformed states at comparable energies, and allows us to track the emergence of the $N=20$ island of inversion through the continuous IMSRG evolution of the chiral Hamiltonian. Our results indicate that the ground state of ${}^{33}$Mg with spin-parity $3/2^{-}$ is predominantly a strongly deformed configuration with $K^{\pi }=3/2^{-}$, while the lowest $7/2^{-}$ state is predicted to be a shape isomer, consisting of a mixture of weakly deformed configurations with different $K$ values. The results highlight the essential roles of both dynamical and static collective correlations in reproducing the ordering of nuclear states with distinct shapes.

arXiv comment8 pages with 5 figures and 1 table, to appear in Phys. Lett. B

References in corpus (57)

• Modern Theory of Nuclear Forces
• Chiral effective field theory and nuclear forces
• Accurate Charge-Dependent Nucleon-Nucleon Potential at Fourth Order of Chiral Perturbation Theory
• The Shell Model as Unified View of Nuclear Structure
• Quantum Monte Carlo methods for nuclear physics
• Improved nuclear matter calculations from chiral low-momentum interactions
• Coupled-cluster computations of atomic nuclei
• From low-momentum interactions to nuclear structure
• The In-Medium Similarity Renormalization Group: A Novel Ab Initio Method for Nuclei
• Evolution of shell structure in exotic nuclei
• Recent developments in no-core shell-model calculations
• Lattice simulations for few- and many-body systems
• A nucleus-dependent valence-space approach to nuclear structure
• A Guided Tour of Ab Initio Nuclear Many-Body Theory
• Ab initio predictions link the neutron skin of ${}^{208}$Pb to nuclear forces
• In-Medium Similarity Renormalization Group for Nuclei
• Non-Empirical Interactions for the Nuclear Shell Model: An Update
• Ab initio limits of atomic nuclei
• Ab Initio Calculations of Even Oxygen Isotopes with Chiral Two- Plus Three-Nucleon Interactions
• Leading chiral three-nucleon forces along isotope chains in the calcium region
• Ab Initio Treatment of Collective Correlations and the Neutrinoless Double Beta Decay of ${}^{48}$Ca
• The merging of the islands of inversion at N=20 and N=28
• In-Medium Similarity Renormalization Group for Open-Shell Nuclei
• The Magnus expansion and the in-medium similarity renormalization group
• Symmetry-guided large-scale shell-model theory
• Physics of nuclei: Key role of an emergent symmetry
• Configuration mixing of angular-momentum projected triaxial relativistic mean-field wave functions. II. Microscopic analysis of low-lying states in magnesium isotopes
• Ab initio multi-shell valence-space Hamiltonians and the island of inversion
• Beyond the relativistic mean-field approximation: configuration mixing of angular momentum projected wave functions
• Exotic neutron-rich medium-mass nuclei with realistic nuclear forces
• Ab initio electromagnetic observables with the in-medium similarity renormalization group
• Ab Initio Description of Open-Shell Nuclei: Merging No-Core Shell Model and In-Medium Similarity Renormalization Group
• Unveiling the intruder deformed 0${}_2^{+}$ state in ${}^{34}$Si
• In-Medium Similarity Renormalization Group for Closed and Open-Shell Nuclei
• Systematics of low-lying states of even-even nuclei in the neutron-deficient lead region from a beyond-mean-field calculation
• Non-observable nature of the nuclear shell structure. Meaning, illustrations and consequences
• Angular-momentum projection in coupled-cluster theory: structure of ${}^{34}$Mg
• Generator-coordinate reference states for spectra and $0\nu \beta \beta$ decay in the in-medium similarity renormalization group
• Testing microscopically derived descriptions of nuclear collectivity: Coulomb excitation of 22Mg
• Shape coexistence near the neutron number N=20: First identification of the E0 decay from the deformed 0^+_2 state in 30Mg
• Multi-reference many-body perturbation theory for nuclei III -- Ab initio calculations at second order in PGCM-PT
• Description of quadrupole collectivity in N ~ 20 nuclei with techniques beyond the mean field
• Projection on particle number and angular momentum: Example of triaxial Bogoliubov quasiparticle states
• Emergence of rotational bands in ab initio no-core configuration interaction calculations of the Be isotopes
• Systematics of E2 strength in the sd-shell with the valence-space in-medium similarity renormalization group
• Ab initio uncertainty quantification of neutrinoless double-beta decay in ${}^{76}$Ge
• Impact of two-body currents on magnetic dipole moments of nuclei
• Ab initio benchmarks of neutrinoless double beta decay in light nuclei with a chiral Hamiltonian
• Exploring the "Island of Inversion" by in-beam gamma-ray spectroscopy of the neutron-rich sodium isotopes 31,32,33Na
• Magnetic moments of ${}^{33}$Mg in time-odd relativistic mean field approach
• Ab initio computations of strongly deformed nuclei around ${}^{80}$Zr
• IMSRG with flowing 3 body operators, and approximations thereof
• Spectroscopy of ${}^{33}$Mg with knockout reactions
• Quadrupole Moments of 29Mg and 33Mg
• In-beam $\gamma$-ray spectroscopy of ${}^{32}$Mg via direct reactions
• Refined topology of the N = 20 island of inversion with high precision mass measurements of ${}^{31-33}$Na and ${}^{31-35}$Mg
• Quantum-number projected generator coordinate method for ${}^{21}$Ne with a chiral two-nucleon-plus-three-nucleon interaction

Cited by in corpus (5)

• Electromagnetic moments in the Sn-Gd region determined within nuclear DFT
• Ab initio study of island of inversion in odd-$A$ nuclei: Structure of ${}^{31,33}$Mg
• Bohr-Mottelson Hamiltonian with octic potential applied to the ${}^{106-116}$Cd isotopes
• Multiple shape coexistence near Sn118: First 03+ lifetime measurement
• Ab initio study in the island of inversion within the two-major-shell valence space