Nuclear deformation in the laboratory frame

Abstract

We develop a formalism for calculating the distribution of the axial quadrupole operator in the laboratory frame within the rotationally invariant framework of the configuration-interaction shell model. The calculation is carried out using a finite-temperature auxiliary-field quantum Monte Carlo method. We apply this formalism to isotope chains of even-mass samarium and neodymium nuclei, and show that the quadrupole distribution provides a model-independent signature of nuclear deformation. Two technical advances are described that greatly facilitate the calculations. The first is to exploit the rotational invariance of the underlying Hamiltonian to reduce the statistical fluctuations in the Monte Carlo calculations. The second is to determine quadruple invariants from the distribution of the axial quadrupole operator. This allows us to extract effective values of the intrinsic quadrupole shape parameters without invoking an intrinsic frame or a mean-field approximation.

12 pages, 8 figures, and 1 table. Added two references; minor changes in the text

References in corpus (13)

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Cited by in corpus (10)

• The Neutron-Rich Edge of the Nuclear Landscape. Experiment and Theory
• The quest of shape coexistence in Zr isotopes
• Statistical theory of deformation distributions in nuclear spectra
• Disappearance of nuclear deformation in hypernuclei: a perspective from a beyond-mean-field study
• Shape coexistence in Sr isotopes
• Convergence of electric quadrupole rotational invariants from the nuclear shell model
• State densities of heavy nuclei in the static-path plus random-phase approximation
• Broken axial symmetry as essential feature for a consistent modelling of various observables in heavy nuclei
• Nuclear level densities: from empirical models to microscopic methods
• Nuclear deformation in the configuration-interaction shell model