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Nuclear Theory·nucl-th

Monday·January 3, 2022

12 papers—3 primary·9 cross-listed

All12Primary3Cross-lists9
  1. 01

    Superfluid density in disordered pasta phases in neutron star crusts

    Zhao-Wen Zhang · C. J. Pethick

    We calculate the superfluid density of nucleons in disordered pasta phases in the inner crust of neutron stars using an effective medium approach which parallels that previously used for calculating the electrical conductivity of terrestrial matter. We allow for the effect of entrainment, the fact that the current density of one species of nucleon depends on the gradient of the phase not only of the same species but also of the other species. The superfluid density tensors for the perfectly ordered pasta phases are very anisotropic, and we derive expression for the effective superfluid densities of the disordered phases.

    nucl-thPRC(2022)·3 citations
  2. 02

    Nuclear states projected from a pair condensate

    Yi Lu · Yang Lei · Calvin W. Johnson · Jia Jie Shen

    Atomic nuclei exhibit deformation, pairing correlations, and rotational symmetries. To meet these competing demands in a computationally tractable formalism, we revisit the use of general pair condensates with good particle number as a trial wave function for even-even nuclei. After minimizing the energy of the condensate, we project out states with good angular momentum with a fast projection technique, allowing for general triaxial deformations. To show applicability, we present example calculations from pair condensates in several model spaces, and compare against projected Hartree-Fock and full configuration-interaction shell model calculations. This approach successfully generates spherical, vibrational and rotational spectra, demonstrating potential for modeling medium- to heavy-mass nuclei.

    nucl-thPRC(2022)·13 citations
  3. 03

    Entanglement and seniority

    J. Kovács · A. T. Kruppa · P. Salamon · Ö. Legeza · G. Zaránd

    We study mode-entanglement in the seniority model, derive analytic formulas for the one-body reduced density matrix of states with seniority , and , and also determine the particle number dependence of the one-body reduced density matrix for arbitrary seniority. We carry out numerical calculations for the lightest calcium isotopes and for nucleus, and investigate the structure of their ground and low energy yrast states. We investigate the fulfillment of several predictions of the seniority model regarding the behavior of one-mode entropies, which we compare with the results of configuration interaction (CI) and density matrix renormalization group (DMRG) computations. For , the seniority model accounts for the mode entropies, but seniority mixing is important for certain yrast states. Interaction induced quantum fluctuations decrease the occupation of the , and shells, and amount in finite mode entropies on these shells, too, clearly outside the scope of the simple seniority model. The shell based seniority model is more accurate for the light isotopes, but seniority mixing is substantial for some yrast states, too.

    nucl-thcond-mat.str-elphysics.chem-phPRC(2022)·43 citations

Affiliations

first authorsco-authorsvia INSPIRE