13,928 research outputs found
Non-local mean field effect on nuclei near Z=64 sub-shell
Evolutions of single-particle energies and Z=64 sub-shell along the isotonic
chain of N=82 are investigated in the density dependent relativistic
Hartree-Fock (DDRHF) theory in comparison with other commonly used mean field
models such as Skyrme HF, Gogny HFB and density dependent relativistic Hartree
model (DDRMF). The pairing is treated in the BCS scheme, except for Gogny HFB.
It is pointed out that DDRHF reproduces well characteristic features of
experimental -dependence of both spin orbital and pseudo-spin orbital
splittings around the sub-shell closure Z=64. Non-local exchange terms of the
isoscalar and couplings play dominant roles in the
enhancements of the spin-orbit splitting of proton 2d states, which is the key
ingredient to give the Z=64 sub-shell closure properly. On the other hand, the
and tensor contributions for the spin-orbit splitting cancel each
other and the net effect becomes rather small. The enhancement of the sub-shell
gaps towards Z=64 is studied by the DDRHF, for which the local terms of the
scalar and vector meson couplings are found to be important.Comment: 4 figure
A note about the mixed regularity of Schr\"odinger Coulomb system
We give a short and unified proof of mixed regularity of Coulomb system for several cases: antisymmetric case with order of derivatives smaller than which is the best bound; mixture of antisymmetry and non-antisymmetry with order of derivatives and respevtively for , and which is also the oprtimal bound; and purely non-antisymmetric case with order of derivatives up to . In addition to Hardy type inequality, it is based on the Herbst inequality. Such results are of particular importance for the study of sparse grid-like expansions of the wavefunctions. Moreover, we can get how fast the norm of these derivative can increase with the number of electrons
Relativistic Hartree-Fock theory. Part I: density-dependent effective Lagrangians
Effective Lagrangians suitable for a relativistic Hartree-Fock description of
nuclear systems are presented. They include the 4 effective mesons and with density-dependent meson-nucleon couplings. The
criteria for determining the model parameters are the reproduction of the
binding energies in a number of selected nuclei, and the bulk properties of
nuclear matter (saturation point, compression modulus, symmetry energy). An
excellent description of nuclear binding energies and radii is achieved for a
range of nuclei encompassing light and heavy systems. The predictions of the
present approach compare favorably with those of existing relativistic mean
field models, with the advantage of incorporating the effects of pion-nucleon
coupling.Comment: 26 pages, 5 table
Neutron star properties in density-dependent relativistic Hartree-Fock theory
With the equations of state provided by the newly developed density dependent
relativistic Hartree-Fock (DDRHF) theory for hadronic matter, the properties of
the static and -equilibrium neutron stars without hyperons are studied
for the first time, and compared to the predictions of the relativistic mean
field (RMF) models and recent observational data. The influences of Fock terms
on properties of asymmetric nuclear matter at high densities are discussed in
details. Because of the significant contributions from the - and
-exchange terms to the symmetry energy, large proton fractions in
neutron stars are predicted by the DDRHF calculations, which strongly affect
the cooling process of the star. The critical mass about 1.45 , close
to the limit 1.5 determined by the modern soft X-ray data analysis,
is obtained by DDRHF with the effective interactions PKO2 and PKO3 for the
occurrence of direct Urca process in neutron stars. The maximum masses of
neutron stars given by the DDRHF calculations lie between 2.45 M and
2.49 M, which are in reasonable agreement with high pulsar mass from PSR B1516+02B. It is also found that the mass-radius
relations of neutron stars determined by DDRHF are consistent with the
observational data from thermal radiation measurement in the isolated neutron
star RX J1856, QPOs frequency limits in LMXBs 4U 0614+09 and 4U 1636-536, and
redshift determined in LMXBs EXO 0748-676.Comment: 28 pages, 11 figure
Spin symmetry in Dirac negative energy spectrum in density-dependent relativistic Hartree-Fock theory
The spin symmetry in the Dirac negative energy spectrum and its origin are
investigated for the first time within the density-dependent relativistic
Hartree-Fock (DDRHF) theory. Taking the nucleus O as an example, the
spin symmetry in the negative energy spectrum is found to be a good
approximation and the dominant components of the Dirac wave functions for the
spin doublets are nearly identical. In comparison with the relativistic Hartree
approximation where the origin of spin symmetry lies in the equality of the
scalar and vector potentials, in DDRHF the cancellation between the Hartree and
Fock terms is responsible for the better spin symmetry properties and
determines the subtle spin-orbit splitting. These conclusions hold even in the
case when significant deviations from the G-parity values of the
meson-antinucleon couplings occur.Comment: 13 pages, 7 figures, 1 table, accepted by Eur. Phys. J.
Prime ideals and Godel ideals of BL-algebras
In this paper we give further properties of ideals of a BL-algebra. The concepts of prime ideals, irreducible ideals and Godel ideals are introduced. We prove that the concept of prime ideals coincides with one of irreducible ideals, and establish the Prime Ideal Theorem in BL-algebras. As applications of Prime ideal Theorem we give several representation and decomposition properties of ideals in BL-algebras. In particular, we give some equivalent conditions of Godel ideals and prove that a BL-algebra A satisfying condition (C) is a Godel algebra i the ideal f0g is a Godel ideal i all ideals of A are Godel ideals if and only if for any  
Shell Structure and -Tensor Correlations in Density-Dependent Relativistic Hartree-Fock theory
A new effective interaction PKA1 with -tensor couplings for the
density-dependent relativistic Hartree-Fock (DDRHF) theory is presented. It is
obtained by fitting selected empirical ground state and shell structure
properties. It provides satisfactory descriptions of nuclear matter and the
ground state properties of finite nuclei at the same quantitative level as
recent DDRHF and RMF models. Significant improvement on the single-particle
spectra is also found due to the inclusion of -tensor couplings. As a
result, PKA1 cures a common disease of the existing DDRHF and RMF Lagrangians,
namely the artificial shells at 58 and 92, and recovers the realistic sub-shell
closure at 64. Moreover, the proper spin-orbit splittings and well-conserved
pseudo-spin symmetry are obtained with the new effective interaction PKA1. Due
to the extra binding introduced by the -tensor correlations, the balance
between the nuclear attractions and the repulsions is changed and this
constitutes the physical reason for the improvement of the nuclear shell
structure.Comment: 20 pages, 11 figures, 6 table
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