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Nuclear Theory·nucl-th

Monday·December 11, 2017

10 papers—6 primary·4 cross-listed

All10Primary6Cross-lists4
  1. 01

    Microscopic optical potentials derived from ab initio translationally invariant nonlocal one-body densities

    Michael Gennari · Matteo Vorabbi · Angelo Calci · Petr Navratil

    We derive a microscopic optical potential for intermediate energies using ab initio translationally invariant nonlocal one-body nuclear densities computed within the no-core shell model (NCSM) approach utilizing two- and three-nucleon chiral interactions as the only input. The optical potential is derived at first-order within the spectator expansion of the non-relativistic multiple scattering theory by adopting the impulse approximation and using the same chiral nucleon-nucleon interaction as that used to compute densities. The ground state local and nonlocal densities of 4,6,8He, 12C, and 16O are calculated and applied to optical potential construction. The differential cross sections and the analyzing powers for the elastic proton scattering off of these nuclei are then calculated for different values of the incident proton energy. The impact of nonlocality and the COM removal is discussed. The use of nonlocal densities has a substantial impact on the differential cross sections and improves agreement with experiment in comparison to results generated with the local densities especially for light nuclei.

    nucl-thPRC(2018)·50 citations
  2. 02

    Comparative study of the requantization of the time-dependent mean field for the dynamics of nuclear pairing

    F. Ni · T. Nakatsukasa

    To describe quantal collective phenomena, it is useful to requantize the time-dependent mean-field dynamics. We study the time-dependent Hartree-Fock-Bogoliubov (TDHFB) theory for the two-level pairing Hamiltonian, and compare results of different quantization methods. The one constructing microscopic wave functions, using the TDHFB trajectories fulfilling the Einstein-Brillouin-Keller quantization condition, turns out to be the most accurate. The method is based on the stationary-phase approximation to the path integral. We also examine the performance of the collective model which assumes that the pairing gap parameter is the collective coordinate. The applicability of the collective model is limited for the nuclear pairing with a small number of single-particle levels, because the pairing gap parameter represents only a half of the pairing collective space.

    nucl-thPRC(2018)·4 citations
  3. 03

    Two-body contributions to the effective mass in nuclear effective interactions

    D. Davesne🇫🇷 · J. Navarro🇪🇸 · J. Meyer🇫🇷 · K. Bennaceur🇫🇷 · A. Pastore🇬🇧

    Starting from general expressions of well-chosen symmetric nuclear matter quantities derived for both zero- and finite-range effective theories, we derive the contributions to the effective mass. We first show that, independently of the range, the two-body contribution is enough to describe correctly the saturation mechanism but gives an effective mass value around . Then, we show that the full interaction (by instance, an effective two-body density-dependent term on top of the pure two-body term) is needed to reach the accepted value .

    nucl-thPRC(2018)·19 citations
  4. 04

    Combining symmetry breaking and restoration with configuration interaction: extension to z-signature symmetry in the case of the Lipkin Model

    Julien Ripoche🇫🇷 · Thomas Duguet🇧🇪 · Jean-Paul Ebran🇫🇷 · Denis Lacroix🇫🇷

    Background: Ab initio many-body methods whose numerical cost scales polynomially with the number of particles have been developed over the past fifteen years to tackle closed-shell mid-mass nuclei. Open-shell nuclei have been further addressed by implementing variants based on the concept of spontaneous symmetry breaking (and restoration). Purpose: In order to access the spectroscopy of open-shell nuclei more systematically while controlling the numerical cost, we design a novel many-body method that combines the merit of breaking and restoring symmetries with those brought about by low-rank individual excitations. Methods: The recently proposed truncated configuration-interaction method based on optimized symmetry-broken and -restored states is extended to the z-signature symmetry associated with a discrete subgroup of SU(2). The highly-truncated N-body Hilbert subspace within which the Hamiltonian is diagonalized is spanned by a z-signature broken and restored Slater determinant vacuum and associated low-rank excitations. Results: The proposed method provides an excellent reproduction of the ground-state energy and of low-lying excitation energies of various z-signatures and total angular momenta. In doing so, the successive benefits of (i) breaking the symmetry, (ii) restoring the symmetry, (iii) including low-rank particle-hole excitations and (iv) optimizing the amount by which the underlying vacuum breaks the symmetry are illustrated. Conclusions: The numerical cost of the newly designed variational method is polynomial with respect to the system size. The present study confirms the results obtained previously for the attractive pairing Hamiltonian in connection with the breaking and restoration of U(1) global gauge symmetry. These two studies constitute a strong motivation to apply this method to realistic nuclear Hamiltonians.

    nucl-thcond-mat.supr-conPRC(2018)·9 citations
  5. 05

    Meson effect in the proto neutron star PSR J0348+0432

    Xian-Feng Zhao🇨🇳

    The effect of mesons (named as ), (named as ) and on the moment of inertia of the PNS PSR J0348+0432 is examined in the framework of the relativistic mean field theory considering the baryon octet. It is found that the energy density and pressure will increase considering the mesons whereas will decrease as the mesons and being considered. When the mesons and are considered, the energy density and pressure will all decrease. It is also found that the contribution of mesons , and to the central energy density is only the central energy density's 0.060.6\% whereas the contribution of mesons , and to the central pressure is the central pressure's 47\%. For the radius, it will decrease when the contributions of mesons , and are considered. The moment of inertia will increase considering the mesons whereas will decrease as the mesons and being considered. When the mesons , and are all considered, the moment of inertia will decrease. It is found that the contribution of mesons and to moment of inertia is 49 times larger than that of mesons . Our results show that the mesons , and contribute to the moment of inertia's 25\%.

    nucl-thInt.J.Theor.Phys.(2017)·2 citations
  6. 06

    Microscopic analysis of Li nuclei cluster photodisintegration reaction characteristics in broad energy range: from threshold until 100 MeV

    M.A. Zhusupov · K.A. Zhaksybekova · R.S. Kabatayeva

    On the base of potential theory of light nuclei cluster photodisintegration the characteristics of Lithium nuclei cluster photodisintegration reactions are considered in the range of low and intermediate energies. For the inverse reaction the interference has an opposite character: in forward semisphere it is deconstructive, and in backward semisphere it is constructive. In the energy range above several MeV the E2-multipole becomes dominating. The effect of appearance of the node structure of the wave function of relative motion has been considered in the characteristics of Li cluster photodisintegration reaction with polarized and non-polarized photons.

    nucl-th0 citations

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first authorsco-authorsvia INSPIRE