Relativistic Brueckner-Hartree-Fock Theory for Finite Nuclei

Starting with a bare nucleon-nucleon interaction, for the first time the full relativistic Brueckner Hartree-Fock equations are solved for finite nuclei in a Dirac-Woods-Saxon basis. No free parameters are introduced to calculate the ground-state properties of finite nuclei. The nucleus 160 is investigated as an example. The resulting groundstate properties, such as binding energy and charge radius, are considerably improved as compared with the non-relativistic Brueckner-Hartree-Fock results and much closer to the experimental data. This opens the door for ab initio covariant investigations of heavy nuclei.

The Brueckner-Hartree-Fock Equation of State for Nuclear Matter and Neutron Skin

The equation of state for nuclear matter is presented within the Brueckner Hartree-Fock （BHF） scheme, by using the realistic Argonne VI8 or Bonn B two-nucleon potentials plus their corresponding microscopic three-nucleon forces. It is then applied to calculate the properties of finite nuclei within a simple liquid-drop model, and we compare the calculated volume, surface, and Coulomb parameters with the empirical ones from the liquid drop model. Nuclear density distributions and charge radii in good agreement with the experimental data are obtained~ and we predict the neutron skin thickness of various nuclei.

Neutron matter properties from relativistic Brueckner-Hartree-Fock theory in the full Dirac space

A novel description of the strongly interacting pure neutron matter(PNM)was carried out by the relativistic Brueckner-HartreeFock(RBHF)theory in the full Dirac space with Bonn A potential.The scalar and vector components of the single-particle potentials are shown as functions of the momentum and the density,and are compared with the results obtained by the RBHF calculations in the Dirac space without negative-energy states.By benchmarking the binding energies of PNM to those predicted by several ab initio methods in the nonrelativistic framework with two-and three-body forces,we find our results are softer than those from the Brueckner-Hartree-Fock theory with the inclusion of three-body force,and in harmony with the ones obtained by the Monte Carlo method and many-body perturbation theory within uncertainties.In addition,the equation of state for neutron star matter is consistent with the constraints from multi-messenger astrophysical observation and heavy-ion collision experiments.The tidal deformabilities of a binary neutron star system are calculated and found consistent with the constraints from GW170817.

Nuclear liquid-gas phase transition within a Brueckner-Hartree-Fock approach

The critical parameters of the liquid-gas phase transition of symmetric nuclear matter are computed using the Brueckner-Hartree-Fock method at finite temperature by employing different realistic nucleon-nucleon potentials.Temperature effects on single-particle potentials,defect functions,and three-body forces are discussed in detail.Results obtained from the full procedure and frozen-correlations approximation are compared.We find critical temperatures of approximately 14 to 19 MeV and critical densities in the range of 0.05 to 0.08fm^(-3),depending on the interactions employed.

Effect of Nucleon Superfluidity and Its Uncertainty on the Neutron Star Cooling

We calculate the cooling curves of superfluid neutron stars with the Brueckner-Hartree-Fock(BHF)equation of state(EOS)by employing the AV18 two body force with a microscopic three body force.The gap energy is calculated within the BCS theory,including in the pairing interaction not only two body force but also three body force.The calculated cooling curves show that the nucleon superfluidity strongly reduces the difference between standard and enhanced cooling.This enables one to explain the majority of observational data by the enhanced cooling of the stars with superfluid cores.The possibility of strong direct Urca processes still cannot be excluded from the cooling analysis.

Spin—Polarized States of Nuclear Matter

The equations of state of spin-polarized nuclear matter and pure neutron matter are studied in the framework of the Brueckner–Hartree–Fock theory including a three-body force. The energy per nucleon EA(δ) calculated in the full range of spin polarization for symmetric nuclear matter and pure neutron matter fulfills a parabolic law. In both the cases the spin-symmetry energy is calculated as a function of the baryonic density along with the related quantities such as the magnetic susceptibility and the Landau parameter G0. The main effect of the three-body force is to strongly reduce the degenerate Fermi gas magnetic susceptibility even more than the value with only two-body force. The equation of state is monotonically increasing with the density for all spin-aligned configurations studied here so that no any signature is found for a spontaneous transition to a ferromagnetic state.

Nucleon ~3pF_2 Superfluid Pairing Gap in Asymmetry Nuclear Matter

The 3 P F2 superfluidity of neutron and proton is investigated in isospin-asymmetric nuclear matter within the Brueckner-Hartree-Fock approach and the BCS theory by adopting the Argonne V14 and the Argonne V18 nucleonnucleon interactions. We find that pairing gaps in the 3PF2 channel predicted by adopting the AV14 interaction are much larger than those by the AV18 interaction. As the isospin-asymmetry increases, the neutron 3 pF2 superfluidity is found to increase rapidly, whereas the proton one turns out to decrease and may even vanish at high enough asymmetries. As a consequence, the neutron 3pF2 superfluidity is much stronger than the proton one at high asymmetries and it predominates over the proton one in dense neutron-rich matter.

^3PF2 neutron superfluidity in neutron stars and three-body force effect

We investigate the ^3PF2 neutron superfluidity in H-stable neutron star matter and neutron stars by using the BCS theory and the Brueckner-Hartree-Fock approach. We adopt the Argonne V18 potential supplemented with a microscopic three-body force as the realistic nucleon-nucleon interaction. We have concentrated on studying the threebody force effect on the ^3PF2 neutron pairing gap. It is found that the three-body force effect is to enhance remarkably the ^3PF2 neutron superfluidity in neutron star matter and neutron stars.

核物质和中子星物质的相对论第一性原理研究

相对论Brueckner-Hartree-Fock(RBHF)理论是相对论框架下重要的第一性原理方法,仅包含两体力即可以满意描述核物质的饱和性质。在完备的Dirac空间中自洽求解核物质RBHF方程,唯一确定了单粒子势的标量和矢量分量,避免了已有工作中由于忽略负能态所导致的不确定性,解决了40多年来RBHF计算中不能唯一确定单粒子势的问题。本工作简要回顾RBHF理论的发展历史,阐述包含负能态做RBHF计算的必要性,介绍利用完备Dirac空间的RBHF理论,研究核物质性质和中子星物质性质的最新进展,包括有效质量、纯中子物质的每核子结合能、对称核物质和纯中子物质的压强、中子星物质的粒子分数和状态方程、中子星的质量-半径关系和潮汐形变等。最后展望了完备Dirac空间的RBHF理论在确定密度泛函理论参数、微观描述核子-原子核弹性散射和研究中子星内部强子-夸克相变等方面的可能应用。

非对称核物质中同位旋对称势的动量和密度依赖性

在Brueckner-Hartree-Fock理论框架内,研究了同位旋非对称核物质中质子和中子单粒子势的动量相关性及其随同位旋非对称度的变化,在此基础上计算了同位旋对称势,并讨论了三体核力的影响.结果表明同位旋对称势对于同位旋非对称度的依赖性很弱,但对于动量和密度均有较强的依赖性.当密度固定时,同位旋对称势随动量增加而减小.尽管三体核力对于质子和中子单粒子势的动量相关性有较大影响,但对同位旋对称势的影响很小.还与目前重离子碰撞输运理论模型中所使用的各种参数化的唯象对称势进行了比较.

自旋极化中子物质的状态方程

在Brueckner-Hartree-Fock理论框架内,研究了自旋极化的中子物质的状态方程及其自旋依赖性,计算了自旋非对称能及相关的物理量如磁化率和朗道参数G_0,并着重讨论了三体核力的影响,结果表明:在整个自旋极化度范围内,中子物质的每核子能量随自旋极化度的变化都满足二次方规律,自旋对称能随密度单调增加,这意味着中子物质中不会发生由自旋非极化态向自旋极化态的自发相变,三体核力的主要效应是使中子物质磁化率随密度减小的速度加快,从而使中子物质的磁化相变更加困难。

非对称核物质不可压缩系数的微观计算(英文)

在带微观三体力的Brueckner-Hartree-Fock方法下研究了非对称核物质的不可压缩系数,得到了不可压缩系数的同位旋以及密度依赖,并做了进一步的讨论。在一定密度下,不可压缩系数作为同位旋非对称度的函数随同位旋单调递增。预测了非对称核物质在平衡态的同位旋依赖性质并与其他理论方法做了比较。

对称核物质中核子-核子散射截面的研究

在扩展的Brueckner-Hartree-Fock(BHF)理论框架下,采用Argonne V14两体相互作用势研究了对称核物质中核子-核子散射的总截面和微分截面,分别讨论了三体核力(TBF)重排效应和基态关联效应对全同和非全同核子散射截面的影响。计算表明:低动量区域的基态关联效应会导致介质中核子-核子散射截面的增大;而随着密度的增加,TBF重排效应的逐渐加强会减小介质中的核子-核子散射截面。

Three-body force effect on the properties of nuclear matter under the gap and continuous choices within the BHF approach

We have calculated and compared the three-body force effects on the properties of nuclear matter under the gap and continuous choices for the self-consistent auxiliary potential within the Brueckner-Hartree-Fock approach by adopting the Argonne Vls and the Bonn B two-body potentials plus a microscopic three-body force （TBF）. The TBF provides a strong repulsive effect on the equation of state of nuclear matter at high densities for both the gap and continuous choices. The saturation point turns continuous choice is adopted. In addition, the dependence self-consistent auxiliary potential is discussed. out to be much closer to the empirical value when the of the calculated symmetry energy upon the choice of the

Effect of tensor force on the density dependence of symmetry energy within the BHF framework

The effect of tensor force on the density dependence of nuclear symmetry energy has been investigated within the framework of the Brueckner-Hartree-Fock （BHF） approach. It is shown that the tensor force manifests its effect via the tensor 3SD1 channel. The density dependence of symmetry energy Esym turns out to be determined essentially by the tensor force from the π meson and p meson exchanges via the 3SD1 coupled channel. Increasing the strength of the tensor component due to the p-meson exchange tends to enhance the repulsion of the equation of state of symmetric nuclear matter and leads to the reduction of symmetry energy. The present results confirm the dominant role played by the tensor force in determining nuclear symmetry energy and its density dependence within the microscopic BHF framework.

Decomposition of the equation of state of asymmetric nuclear matter into different spin-isospin channels

We investigate the equation of state of asymmetric nuclear matter and its isospin dependence in various spin-isospin ST channels within the framework of the Brueckner-Hartree-Fock approach extended to include a microscopic three-body force（TBF） . It is shown that the potential energy per nucleon in the isospinsinglet T = 0 channel is mainly determined by the contribution from the tensor SD coupled channel. At high densities,the TBF effect on the isospin-triplet T = 1 channel contribution turns out to be much larger than that on the T =0 channel contribution. At low densities around and below the normal nuclear matter density,the isospin dependence is found to come essentially from the isospin-singlet SD channel and the isospin-triplet T = 1 component is almost independent of isospin asymmetry. As the density increases,the T = 1 channel contribution becomes sensitive to the isospin asymmetry and at high enough densities its isospin dependence may even become more pronounced than that of the T = 0 contribution. The present results may provide some microscopic constraints for improving effective nucleon-nucleon interactions in a nuclear medium and for constructing new functionals of effective nucleon-nucleon interaction based on microscopic many-body theories.

Single particle potentials of asymmetric nuclear matter in different spin-isospin channels

We investigate the neutron and proton single particle （s.p.） potentials of asymmetric nuclear matter and their isospin dependence in various spin-isospin ST channels within the framework of the BruecknerHartree-Fock approach. It is shown that in symmetric nuclear matter, the s.p. potentials in both the isospinsinglet T = 0 channel and isospin-triplet T = 1 channel are essentially attractive, and the magnitudes in the two different channels are roughly the same. In neutron-rich nuclear matter, the isospin-splitting of the proton and neutron s.p. potentials turns out to be mainly determined by the isospin-singlet T = 0 channel contribution which becomes more attractive for the proton and more repulsive for the neutron at higher asymmetries.