Browsing by Author "Tong, Hui"

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    Relativistic Brueckner-Hartree-Fock theory in nuclear matter without the average momentum approximation
    (American Physical Society, 2018) Tong, Hui; Ren, Xiu-Lei; Ring, Peter; Shen, Shi-Hang; Wang, Si-Bo; Meng, Jie
    Brueckner-Hartree-Fock theory allows one to derive the G matrix as an effective interaction between nucleons in the nuclear medium. It depends on the center-of-mass momentum P of the two particles and on the two relative momenta q and q′ before and after the scattering process. In the evaluation of the total energy per particle in nuclear matter, usually the angle-averaged center-of-mass momentum approximation has been used. We derive in detail the exact expressions of the angular integrations of the momentum P within relativistic Brueckner-Hartree-Fock (RBHF) theory, especially for the case of asymmetric nuclear matter. In order to assess the reliability of the conventional average momentum approximation for the binding energy, the saturation properties of symmetric and asymmetric nuclear matter are systematically investigated based on the realistic Bonn nucleon-nucleon potential. It is found that the exact treatment of the center-of-mass momentum leads to non-negligible contributions to the higher order physical quantities. The correlations between the symmetry energy Esym, the slope parameter L, and the curvature Ksym of the symmetry energy are investigated. The results of our RBHF calculations for the bulk parameters characterizing the equation of state are compared with recent constraints extracted from giant monopole resonance and isospin diffusion experiments.
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    Strength of tensor forces from neutron drops in ab initio relativistic Brueckner-Hartree-Fock theory
    (American Physical Society, 2019) Wang, Sibo; Tong, Hui; Zhao, Pengwei; Meng, Jie
    The evolution of spin-orbit splittings of neutron drops along with the neutron number and its connection with the tensor-force strength have been investigated systematically for different external fields in the relativistic Brueckner-Hartree-Fock (RBHF) and relativistic Hartree-Fock (RHF) theories. Based on the RHF functional PKO1, it is found that a good consistency between the RBHF and RHF results for the total energies can be obtained only for those neutron drops whose central densities are close to the saturation density of nuclear matter. Nevertheless, by rescaling the density dependence of the RHF functional, the RBHF total energies of neutron drops in different external fields can be well reproduced. The optimized tensor-force strength λ in the RHF theory, which reproduces the microscopic RBHF spin-orbit splittings, is running with the strength of the external fields of neutron drops. This provides an important guide for future determination of tensor forces in nuclear energy density functionals based on microscopic ab initio calculations.