Nuclear tensor interaction in a covariant energy density functional

Abstract

The origin of the nuclear tensor interaction in the covariant energy density functional (EDF) is presented in this work, associated with the Fock diagrams of Lorentz scalar and vector couplings. With this newly obtained relativistic formalism of the nuclear tensor interaction, more distinct tensor effects are found in the Fock diagrams of the Lorentz scalar and vector couplings, as compared to the Lorentz pseudovector and tensor channels. A unified and self-consistent treatment of both the nuclear tensor and spin-orbit interactions, which dominate the spin-dependent features of the nuclear force, is then achieved by the relativistic models. Moreover, careful analysis of the tensor strengths indicates the reliability of the nuclear tensor interaction in the covariant EDF for exploring the nuclear structure, excitation, and decay modes.

Impact of Fock terms on the isospin properties of nuclear matter

“…[27,43,[46][47][48]. In RHF theory, the energy density functional (EDF) is obtained by taking the expectation value of the Hamiltonian with respect to the Hartree-Fock ground state, which consists of three parts: the kinetic EDF ε k , the direct (Hartree) ε D φ and the exchange (Fock) ε E φ terms of the potential EDF.…”

“…1 , remarkably negative contribution to E M S,k is found from the isoscalar-meson coupling channel, while relatively weak but still considerable contribution results from the isovector-meson coupling channel, eventually leading to a significant difference in the sign and magnitude of E S,k between RMF and RHF results. In fact, it has been demonstrated very recently that the nuclear tensor in- teractions are naturally embedded in both the isoscalar and the isovector meson-nucleon coupling channels with the presence of the Fock diagrams in the RHF EDF [38,46]. In consequence, the extra contributions from the Fock terms of Σ S to the kinetic symmetry energy could be regarded partly as the effects of the nuclear tensor-force components therein, see Refs.…”

“…The detailed discussion on these topics refers to Refs. [27,43,44,46,47].The general formulae of the DDRHF theory in nuclear matter can be found in Refs. [27,43,[46][47][48].…”

“…In consequence, the extra contributions from the Fock terms of Σ S to the kinetic symmetry energy could be regarded partly as the effects of the nuclear tensor-force components therein, see Refs. [46,47].In short, present status of DDRHF studies on the isospin properties of nuclear matter is summarized, especially the effects of the Fock terms on the nuclear symmetry energy such as those from the hyperon and the nuclear tensor force. The reduction of the kinetic symmetry energy at supranuclear density in DDRHF models is discussed as well, which is related to the fact of a remarkably negative contribution from the isoscalar-meson coupling channel via Fock terms.…”

“…With the growth of computational facilities and the development of new methods, such defects can be eliminated with the inclusion of exchange (Fock) terms, which generates a new CDF model -the relativistic Hartree-Fock (RHF) theory with density-dependent meson-nucleon couplings (i.e., the DDRHF theory) [27]. Substantial improvements are gained by DDRHF in the selfconsistent description of the ground state properties [27][28][29][30][31][32][33][34][35][36][37][38], the excitation modes [39][40][41][42] of finite nuclei and nuclear astrophysics as well [43][44][45][46].It has been shown from several studies that the inclusion of the Fock terms in the CDF theory could improve descriptions of the isospin-related nuclear structure. In fact, non-locality of the mean field induced by the Fock terms gives rise to the momentum dependence of the RHF self-energies, improving the isospin and energy dependence for the nucleon effective mass [27].…”