We compute the free energy of asymmetric nuclear matter in a Brueckner-Hartree-Fock approach at finite temperature, paying particular attention to the dependence on isospin asymmetry. The first- and second-order symmetry energies are determined as functions of density and temperature and useful parametrizations are provided. We find small deviations from the quadratic isospin dependence and very small corresponding effects on (proto)neutron star structure.
In the present work we are going to add a correction to the BHF potential calculation by introducing a two- body density dependent potential that acts as a three body interaction. Adding the result of this potential to the BHF potential would give us new saturation curves which coincide with the results obtained from the experiment. We compute the energy per particle versus density curves for symmetric nuclear matter, pure neutron matter and the symmetry energy using modern nucleon nucleon potentials like CD Bonn.
We analyze the spinodal instabilities of spin polarized asymmetric nuclear matter at zero temperature for several configurations of the neutron and proton spins. The calculations are performed with the Brueckner--Hartree--Fock (BHF) approach using the Argonne V18 nucleon-nucleon potential plus a three-nucleon force of Urbana type. An analytical parametrization of the energy density, which reproduces with good accuracy the BHF results, is employed to determine the spinodal instability region. We find that, independently of the of the orientation of the neutron and proton spins, the spinodal ins…
The self-energy effect on the neutron-proton (np) pairing gap is investigated up to the third order within the framework of the extend Bruecker-Hartree-Fock (BHF) approach combined with the BCS theory. The self-energy up to the second-order contribution turns out to reduce strongly the effective energy gap, while the \emph{renormalization} term enhances it significantly. In addition, the effect of the three-body force on the np pairing gap is shown to be negligible. To connect the present results with the np pairing in finite nuclei, an effective density-dependent zero-range pairing force is e…
Microscopic calculation of neutrino mean free path inside hot neutron matter
在Brueckner-Hartree-Fock近似下，用自洽方法计算了有限温度下纯中子物质的中微子平均自由程和状态方程。我们采用了奈梅亨小组最近建立的现实重子-重子相互作用模型（NSC 97 e）中的核子-核子部分。考虑的温度范围从10到80兆电子伏。本文报道了在Brueckner-Hartree-Fock加随机相位近似（BHF+RPA）框架下计算的平均场、剩余相互作用和中微子平均自由程（包括短程和长程关联）。这是第一次在热中子物质中对中微子平均自由程进行完全自洽的计算，并将我们的结果与D1 P Gogny有效相互作用的结果进行了系统的比较。本计算与核有效相互作用计算之间的主要差异来自RPA对BHF的修正（约为8倍），而温度缺乏一致性约为2倍。
The effective isospin-density dependent pairing interaction (P1) [S. S. Zhang, U. Lombardo and E. G. Zhao, Sci. Chin. Phys. Mech. Astro. {\bf 54}, 236 (2011)] extracted from neutron pairing gaps for $^1$S$_0$ in asymmetric nuclear matter calculations [S. S. Zhang, L. G. Cao, U. Lombardo, et al. Phys. Rev. C {\bf 81}, 044313 (2010)] is employed to study the bulk properties of Ca, Ni, Zr and Sn isotopes. The odd-even mass (OEM) staggering is calculated by the Skyrme Hartree-Fock plus BCS method (SHF + BCS) with the SkP interaction. For comparison, we study two other types of isovector effective …
We present a family of nucleon-nucleon (NN) plus three-nucleon (3N) interactions up to N3LO in the chiral expansion that provides an accurate ab initio description of ground-state energies and charge radii up to the medium-mass regime with quantified theory uncertainties. Starting from the NN interactions proposed by Entem, Machleidt and Nosyk, we construct 3N interactions with consistent chiral order, non-local regulator, and cutoff value and explore the dependence of nuclear observables over a range of mass numbers on the 3N low-energy constants. By fixing these constants using the 3-H and 1…
We optimize $Δ$-full nuclear interactions from chiral effective field theory. The low-energy constants of the contact potentials are constrained by two-body scattering phase shifts, and by properties of bound-state of $A=2$ to $4$ nucleon systems and nuclear matter. The pion-nucleon couplings are taken from a Roy-Steiner analysis. The resulting interactions yield accurate binding energies and radii for a range of nuclei from $A=16$ to $A=132$, and provide accurate equations of state for nuclear matter and realistic symmetry energies. Selected excited states are also in agreement with data.
Towards a better knowledge of the nuclear equation of state from the isoscalar breathing mode
分析了等密度巨磁共振（GMR）（也称为呼吸模式）的测量结果对$M_c$量的约束，例如，在所谓的交叉密度$ρ_c$ =0.1 fm $^{-3}$周围的核不可压缩性的密度依赖性。GMR、$E_\mathrm{GMR}$和$M_c$的质心之间的相关性比$E_\mathrm{GMR}$和饱和密度下的不可压缩模量$K_\infty$之间的相关性更准确，从而改进了对核物质状态方程的测定。$M_c$和$K_\infty$之间的关系作为偏度参数$Q_\infty$的函数给出，偏度参数与状态方程的密度依赖性有关。不同能量密度泛函之间$Q_\infty$的大变化直接影响对$K_\infty$的了解：需要更好地了解$Q_\infty$以更准确地推导出$K_\infty$。使用局部密度近似，一个简单而准确的表达式有关$E_\mathrm{GMR}$和数量$M_c$的推导和成功地比较完全微观预测。
Nuclear physics experiments give reaction rates that, via modelling and comparison with primordial abundances, constrain cosmological parameters. The error bars of a key reaction, \dpg, were tightened in 2020, bringing to light discrepancies between different analyses and calling for more accurate measurements of other reactions.
We have constructed empirical formulae for fusion and interaction barrier heights using experimental values available in the literature. Fusion excitation function measurements are used for the former and back angle quasi-elastic excitation function for the latter case. The fusion barriers so obtained have been compared with various model predictions such as Bass potential, Christenson and Winther, Broglia and Winther, Aage Winther, Siwek-Wilczynska and J.Wilczynski, Skyrme energy density function model, and the Sao Paulo optical potential along with experimental results. The comparison allows…
The nuclear Equation of State (EoS) lies in the center of the nuclear N-body problem as it describes the properties of the Nuclear Matter (NM) and determines the parameters of the nuclear interaction. In this work, we propose a theoretical description of the EoS of both Symmetric (SNM) and Asymmetric (ANM) nuclear matter within the framework of Fermionic Dynamics. With this description we produce several new semi-hard EoS with density dependent effective mass. Finally, we transform the aforementioned theory in order to be consistent with Mean-Field dynamics. We use this approach to accurately …
Construction of Nuclear Covariant Energy Density Functional from A Physics-Guaranteed Neural Network Approach
School of Physics, Anhui University（安徽大学物理学院）；Department of Physics, Graduate School of Science, The University of Tokyo（东京大学理学研究科物理学系）；Quark Nuclear Science Institute, The University of Tokyo（东京大学夸克核科学研究所）；RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS)（理化学所跨学科理论与数学科学中心(iTHEMS)）；School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院）；School of Physics and Nuclear Energy Engineering, Beihang University（北京航空航天大学物理与能源工程学院）
Nucleus-nucleus optical potentials are constructed from an energy density functional approach first outlined by Brueckner et al. The interaction term of the energy density functional comes from the complex nucleon self-energy computed in nuclear matter with two- and three-body chiral nuclear forces. Nuclear density distributions are calculated from Skyrme functionals constrained to the equations of state calculated from the same chiral forces used for the self-energy. Predictions for elastic scattering cross sections and fusion cross sections are compared to experimental data. Very good agreem…
We have extended the compressible liquid-drop model (CLDM) with a density-dependent surface term (eCLDM), which allows for a unified description of both the nuclear ground state energies and the incompressibility modulus in finite nuclei $K_A$. We analyse the role of the nuclear empirical parameters, e.g., $K_{sat}$, $Q_{sat}$, $L_{sym}$ and $K_{sym}$, which contribute to the bulk properties, as well as the role of the finite size contributions. For the bulk properties, the density and isospin dependencies of the nuclear incompressibility in infinite matter are characterized by introducing new…
Full Configuration Interaction Quantum Monte Carlo for Accurate $\textit{Ab Initio}$ Nuclear Structure Calculations
School of Physics, and State Key Laboratory of Nuclear Physics and Technology, Peking University（北京大学物理学院，核物理与技术国家重点实验室）；Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所，南方核科学理论中心）；Max Planck Institute for Solid State Research（马克斯·普朗克固体研究所）；Department of Chemistry, University of Cambridge（剑桥大学化学系）
Full configuration interaction quantum Monte Carlo for accurate $\textit{ab initio}$ nuclear structure calculations: algorithms and calculation details
School of Physics, and State Key Laboratory of Nuclear Physics and Technology, Peking University（北京大学物理学院，核物理与技术国家重点实验室）；Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所南方核科学理论中心(SCNT)）；Max Planck Institute for Solid State Research（马克斯·普朗克固体研究所）；Department of Chemistry, University of Cambridge（剑桥大学化学系）
