相对论Hartree-Fock研究奇特核的性质

采用相对论Hartree-Fock(RHF)理论来描述奇特核的性质.为了研究Fock项和矢量介子对奇特核性质的贡献和避免有效相互作用的不惟一性,本文推广应用没有自由参数的密度有关的相对论Hartree(RDH)和Hartree-Fock(RDHF)理论来描述奇特核的性质.在RDH和RDHF近似下,计算了钙同位素链的性质,特别研究了Fock交换项和矢量介子的贡献.研究表明交换项和矢量介子对非常丰中子核的性质,如结合能,中子均方根半径,中子密度分布的影响是非常不同于对稳定线附近核性质的影响.同时,对研究滴线奇特核性质的重要性及其理论模型做了简单的讨论.     

Effect of trifluoroethylene monomers on molecular conformation of poly（vinylidene fluoride-trifluoroethylene） copolymer

Hartree－Fock and density functional theory (DFT) methods were employed to study poly (vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] molecular chains with different VDF contents. The dependence of dipole moment of P(VDF-TrFE) chains on VDF content obtained from our calculation is in good agreement with the experiment. The TrFE monomer plays an important role in introducing the gauche bond into copolymer chains. A possible mechanism was interpreted.     

Finite temperature aspect ratio in ultra-cold Bose gas for large N

We present a detailed study of the temperature dependence of the condensate fraction, collective excitation and aspect ratio profiles of a Bose-condensed gas in a harmonic trap for large numbers of condensate atoms up to 85000. These quantities are calculated self-consistently using the generalized Hartree–Fock–Bogoliubov (GHFB) equations. We determine the evolution of the aspect ratio at zero and finite temperature via the condensed fraction. We compare our results with experimental data and we find a good agreement.     

Surface Corrugation in Rotational and Diffractive Scattering of O2 from LiF (001)

A quantum dynamic calculation on a five-dimensional O₂/LiF (001) model system is performed using the multi-configuration time-dependent Hartree method. The obtained results show that the mechanism of rotational and diffractive excitation in details: Comparison with the rotational excited state, the initially non-rotational state is seen to favor the inelastic scattering in the rotational excitation process. The surface corrugation can damp the quantum interferences and produce a greater amount of rotational inelastic scattering at the expense of the elastic process in the rotational excitation process. The diffraction process and the average energy transferred into the rotational and diffractive mode are also discussed.     

The fundamental surface science of wurtzite gallium nitride

A review is presented that covers the experimental and theoretical literature relating to the preparation, electronic structure and chemical and physical properties of the surfaces of the wurtzite form of GaN. The discussion includes the adsorption of various chemical elements and of inorganic, organometallic and organic species. The focus is on work that contributes to a microscopic, atomistic understanding of GaN surfaces and interfaces, and the review concludes with an assessment of possible future directions.     

An Exactly Solvable Superfluidity Model and the Phase Transition of the Zeroth Kind (Fountain Effect)

We present an exactly solvable N-particle Schrödinger equation model for symmetric states (bosons), define a phase transition from the metastable (superfluid) state to the normal state for the model, and show that this is a phase transition of the zeroth kind with a free-energy jump and with specific heat tending to infinity. We also show that the asymptotic expression as N for the solution corresponding to the local Gibbs distributions coincides with the solution of the Hartree temperature equation, which illustrates our formula for the dependence of the Landau criterion on temperature in Bogoliubov's almost-ideal Bose gas model.     

Instability of Standing Wave for the Klein–Gordon–Hartree Equation

The instability property of the standing wave uω(t, x) = eiωtφ(x) for the Klein–Gordon– Hartree equation     

Existence and stability of standing waves for nonlinear fractional Schrödinger equations with Hartree type nonlinearity

In this paper, we consider the nonlinear fractional Schrödinger equations with Hartree type nonlinearity. We obtain the existence of standing waves by studying the related constrained minimization problems via applying the concentration-compactness principle. By symmetric decreasing rearrangements, we also show that the standing waves, up to translations and phases, are positive symmetric nonincreasing functions. Moreover, we prove that the set of minimizers is a stable set for the initial value problem of the equations, that is, a solution whose initial data is near the set will remain near it for all time.     

Soliton dynamics for the generalized Choquard equation

We investigate the soliton dynamics for a class of nonlinear Schrödinger equations with a non-local nonlinear term. In particular, we consider what we call generalized Choquard equation   where the nonlinear term is (|x|^θ−N?|u|^p)|u|^p−2u$({|x|}^{\theta -N}?{|u|}^p){|u|}^{p-2}u$. This problem is particularly interesting because the ground state solutions are not known to be unique or non-degenerate.