多分量对偶超导理论和口袋模型

基于联络新参数化方案研究了多分量对偶超导模型。给出了多分量Ginzburg Landau模型中的自对偶解, 并研究了磁通量子数趋于无穷大时的墙涡旋解, 以及与口袋模型之间的联系。The multi-component dual superconductor theory has been studied based on the new parameterization of gauge potential. The self dual vortices of the multi component Ginzburg Landau model was investigated. Then we considered the wall vortex whose flux goes to infinity. At last, the relationship between the bag model and wall vortices is considered.     

强耦合杨-米尔斯理论中的对偶超导真空

基于联络分解变量的紫外/红外分离, 提出杨-米尔斯理论真空的强耦合极限表现为一个经典场论意义下色空间的黑洞. 基于此想法, 证明在强耦合杨-米尔斯理论中存在对偶超导体解. 在量子水平下, 强耦合理论的非微扰真空可由磁荷的多粒子体系构成, 而理论的经典平均给出对偶阿贝尔-黑格斯模型. 该模型预言了与最近的格点模拟相一致的结果: 理论真空位于第一类与第二类超导体边界. 进一步通过求解对偶阿贝尔-黑格斯模型讨论了色电场的对偶迈斯纳效应.     

非Abel对偶超导理论中的涡旋管研究

首次讨论了非Abel对偶超导理论中的涡旋管性质。 在Cho等工作的基础上进一步研究了非Abel情况下的动力学, 并推导出了哈密顿量和运动方程。 重点讨论了限制规范势对应的非Abel对偶超导理论性质, 并给出了D型及N型两类整数涡旋的具体数值解。 通过与传统的Abel对偶超导理论的对比分析,发现两者的运动方程形式及涡旋解基本一致, 这表明利用Abel对偶超导模型研究夸克色禁闭问题是合理的。 We have discussed vortices in the non Abelian dual superconductor theory. Based on the work of Cho et al., the Hamiltonian and the equations of motion of non Abelian model were discussed in details. The non Abelian dual superconductor theory related to the restricted guage potential was underlined and solutions of D type and N type integer vortices were obtained. Comparing with the traditional Abelian dual superconductor theory, we found that the the equations of motion and solutions of vortices in two models are almost same, which indicates it is reasonable to study quark confinement based on the Abelian dual superconductor theory.     

双环形Hulthén势束缚态的近似解析解

构造了双环形Hulthén势, 用指数函数近似表示任意分波的离心项, 运用函数分析法讨论双环型Hulthén势Schrödinger方程的束缚态解. 归一化的角向波函数和径向波函数用超几何多项式表示, 给出了束缚态能谱, 体系的束缚态的能谱方程和波函数与量子数和势参数有关. 中心势场和单环形势场角向波函数及 Hulthén势束缚态能谱是本文双环形Hulthén势的特例. 关键词： 双环形Hulthén势 任意分波 近似解析解 束缚态     

超导纳米线单光子探测器光子响应机制研究进展

超导纳米线单光子探测器(SNSPD)已在量子信息、深空激光通信、激光雷达等众多领域发挥了重要的作用.虽然SNSPD经过二十年的研究,但其光子响应本征机制还有待完善.深入理解与厘清其光子响应过程是研发高性能探测器的前提与关键.现在较为成熟的超导纳米线单光子探测器响应理论有热点模型和涡旋模型.但是这两种理论都存在一定的缺陷...     

基于近似解析法的超导储能磁体设计

降低超导储能磁体的研制成本一直是控制超导磁储能系统(Superconducting Magnetic Energy Storage, SMES)总成本的重要手段之一.本文考虑在一定磁体结构参数范围内,磁体产生的最大磁场值可以采用级数进行表示,磁体的电感值可以采用线性函数表示,给出了超导储能磁体磁场能量的近似解析表达式,提出了一种基于近似解析法的超导储能磁体设计方法.该方法以储能磁体的线材用量最小作为设计目标,在给定超导线材参数和临界电流特性曲线,以及磁体储能总量要求的情况下,依据此方法可快速的得到成本最优时所对应的磁体结构参数.将近似解析法优化和采用传统的有限元软件Ansys仿真优化进行对比分析,结果表明采用近似解析法进行磁体优化更加方便快捷,节省了大量计算时间.     

超导倒挂模型的引力特性研究

通过不同条件下的悬浮力测量实验,研究冷却条件、场冷距离、轴距对单磁体式超导倒挂模型的引力特性的影响,在确定悬浮力的有限元仿真方法可行的基础上,仿真得到组合磁体式超导倒挂模型中不同磁极组合形式下的超导引力特性。实验和仿真结果表明:场冷的退磁过程能够获得较宽的超导引力区域,且场冷距离越小,轴距越小,组合磁体的磁极数越少,引力极大值越大。     

磁场作用下超导圆环的涡旋演化

利用Ginzburg-Landau理论模拟在外磁场作用下超导圆环的涡旋演化,讨论了外磁场、材料参数以及圆环内外径对涡旋进入超导圆环体以及涡旋达到稳定分布的影响.研究结果表明:外磁场越大,材料参数κ越大,圆环环身越宽,则超导圆环体内容纳的涡旋就越多.当磁场较小时,涡旋只由内边界进入超导体,当磁场足够大时,涡旋则先由外边界,然后再从内边界进入超导体.     

用反型层模型探讨n—Ge中的常温反常霍耳效应

本文用反型层模型,对常温下n-Ge中的反常霍耳效应进行了理论上的定量计算,取得了与实验一致的结果。 关键词：     

YBa2Cu3O7—δ超导体的声子—激子联合超导机理模型

本文从声子-激子联合机理模型出发,用推广的 Numbu-Eliashberg 强耦合超导微观理论计算了 YB_2Cu_3O_(6.9)超导体的临界温度 T_c 和氧同位素应 T_c～M_0~(-α_0)的位移系数α_0,结果与实验符合较好.     

Analytical Approximate Solution of SchrSdinger Equation in D Dimensions with Quadratic Exponential-Type Potential for Arbitrary/-State

We present the bound state solution of Schr6dinger equation in D dimensions for quadratic exponential-type potential for arbitrary l-state. We use generalized parametric Nikiforov-Uvarov method to obtain the energy levels and the corresponding eigenfunction in dosed form. We also compute the energy eigenvalues numerically.     

An Approximate Analytical Solution of Imploding Strong Shocks in a Non-Ideal Gas through Lie Group Analysis

The method of Lie group transformation is used to obtain an approximate analytical solution to the system of first-order quasilinear partial differential equations that govern a one-dimensional unsteady planer, cylindrically symmetric and spherically symmetric motion in a non-ideal gas, involving strong shock waves. Invariance groups admitted by the governing system of partial differential equations, which are indeed continuous group of transformations under which the system of partial differential equations remains invariant, are determined, and the complete Lie algebra of infinitesimal symmetries is established. The infinitesimal generators are used to construct the similarity variables. These similarity variables are used to reduce the governing system of partial differential equations into a system of ordinary differential equations.     

Beyond Inverse Ising Model: Structure of the Analytical Solution

I consider the problem of deriving couplings of a statistical model from measured correlations, a task which generalizes the well-known inverse Ising problem. After reminding that such problem can be mapped on the one of expressing the entropy of a system as a function of its corresponding observables, I show the conditions under which this can be done without resorting to iterative algorithms. I find that inverse problems are local (the inverse Fisher information is sparse) whenever the corresponding models have a factorized form, and the entropy can be split in a sum of small cluster contributions. I illustrate these ideas through two examples (the Ising model on a tree and the one-dimensional periodic chain with arbitrary order interaction) and support the results with numerical simulations. The extension of these methods to more general scenarios is finally discussed.     

Mon(n=2-13)和MonC(n=1-12)团簇的几何结构和电子结构

结合遗传算法和CALYPSO软件,采用密度泛函理论,对Mo_n(n=2-13)及Mo_nC(n=1-12)团簇基态的几何结构与电子结构展开详细研究.通过计算其基态结构的平均键长、平均结合能、二阶差分能、分裂能和前线轨道能级,对基态结构的稳定性随总原子数变化的关系展开了研究.计算结果表明,Mo_n团簇基态结构的稳定性可通过掺杂单个C原子而提高.综合团簇的二阶差分能、分裂能可知,n=6,9时Mo_n团簇的稳定性较高,n=4,7,10时Mo_nC团簇的稳定性较高.