Exact diagonalization study of 2D Hubbard model on honeycomb lattice: Semi-metal to insulator transition

Phase transition in a honeycomb lattice is studied by the means of the two-dimensional Hubbard model and the exact diagonalization dynamical mean field theory at zero temperature. At low energies, the dispersion relation is shown to be a linear function of the momentum. In the limit of weak interactions, the system is in the semi-metal phase. By increasing the on site interaction a semi-metal to insulator transition takes place in the paramagnetic phase. Calculation of double occupancy shows such a phase transition is of the second order. The respective phase transition point and critical on-site interaction are determined using renormalized Fermi velocity factor.     

三角对称晶场中6 S(3d5)态离子零场分裂参量的微观起源

基于完全对角化方法(complete diagonalization method, CDM), 研究了⁶ S(3d⁵)态离子在三角晶场(包括C_3v,D₃,D_3d点群对称晶场)中零场分裂(zero-field splitting, ZFS)参量D和(a-F)的微观起源.研究中除了考虑研究者通常考虑的SO(spin-orbit)磁相互作用外,同 关键词： 6 S(3d⁵)态离子')" href="#">⁶ S(3d⁵)态离子 零场分裂参量 磁相互作用 完全对角化方法     

具连续变量和最大值项的二阶差分方程的振动性

研究了一类具有最大值项和连续变量的非线性二阶中立型时滞差分方程的振动性,利用Banach空间的不动点原理和一些不等式技巧,得到了这类方程存在最终正解的充分条件,并得到了该方程振动的一些判别准则.     

关于矩阵对角化的探讨

通过示例探讨了一类可对角化矩阵实施对角化的具体过程.     

Analytical and numerical stability of partial differential equations with piecewise constant arguments

This article is concerned with the stability analysis of the analytic and numerical solutions of a partial differential equation with piecewise constant arguments of mixed type. First, by means of the similar technique in Wiener and Debnath [Int J Math Math Sci 15 (1992), 781–788], the sufficient conditions under which the analytic solutions asymptotically stable are obtained. Then, the θ‐methods are used to solve the above‐mentioned equation, the sufficient conditions for the asymptotic stability of numerical methods are derived. Finally, some numerical experiments are given to demonstrate the conclusions.Copyright © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 1‐16, 2014     

Existence results for problems with deviating arguments

This paper deals with some problems of calculus of variation for functionals with deviating arguments. We use the direct method to establish some existence results and extend the corresponding results obtained in literature.     

ASYMPTOTIC BEHAVIOR OF SOLUTIONS TO A CLASS OF HIGHER ORDER NONLINEAR INTEGRO-DIFFERENTIAL EQUATIONS WITH DEVIATING ARGUMENTS

In this paper,we study the asymptotic behavior of solutions to a class of higher order nonlinear integro-differential equations with deviating arguments. And some properties of the oscillatory solutions are given. Our results generalize and improve the previous results.     

带有多变滞量的高阶非线性中立型差分方程的振动性判据

研究了较为广泛的一类带有多个变滞量的高阶非线性中立型差分方程的振动性,建 立了这类方程振动的一个充要条件和一个充分条件．     

具多滞量的非线性中立型差分方程的振动性定理

研究了一类较为广泛的具有多个滞量的非线性中立型差分方程的振动性，得到了该类方程振动的一个判定定理     

Monotone iterative technique for boundary value problems of a nonlinear fractional differential equation with deviating arguments

By using the method of upper and lower solutions and the monotone iterative technique, we investigate boundary value problems for fractional differential equations with nonlinear boundary conditions and deviating arguments. As an application, an example is presented to illustrate the main results.