非简谐振子与新条件精确可解势

利用超对称性,由平移的非简谐振子构造出了多类新的条件精确可解势,并得到相应的非线性谱生成代数.     

第一类Poschl-Teller势的非线性代数结构

在形变李代数理论的基础上,利用哈密顿算符和自然算符,构造出第一类Poschl-Teller势的非线性谱生成代数。该非线性代数能够完全确定势场的能量本征态集合和本征值谱,在适当的非线性算符变换下可以化为谐振子代数,显示了该系统具有新的对称性。     

量子双阱势准确解模型

Darboux变换和一个积分变换用于变换Poschl-Teller势和改型Poschl-Teller势的薛定谔型方程,求得了两类双阱势可解模型。 关键词：     

第一类PschlTeller势的非线性代数结构

在形变李代数理论的基础上 ,利用哈密顿算符和自然算符 ,构造出第一类P schl Teller势的非线性谱生成代数 .该非线性代数能够完全确定势场的能量本征态集合和本征值谱 ,在适当的非线性算符变换下可以化为谐振子代数 ,显示了该系统具有新的对称性     

第一类P?schl-Teller势的非线性代数结构

在形变李代数理论的基础上,利用哈密顿算符和自然算符,构造出第一类P?schl-Teller势的非线性谱生成代数.该非线性代数能够完全确定势场的能量本征态集合和本征值谱,在适当的非线性算符变换下可以化为谐振子代数,显示了该系统具有新的对称性 关键词： P?schl-Teller势 自然算符 非线性谱生成代数     

幂函数叠加势的形状不变性

用超对称量子力学方法,构造出具有形状不变性的两种幂函数叠加势的形式,并计算了它们的能量本征值.谐振子势、库仑势和Kratzer势等是幂函数叠加势的特例,它们的能级都可由幂函数叠加势的能级中得出.     

具有非局域势的量子力学模型

利用超对称性(SUSY)量子力学讨论能够精确求解的具有非局域势的量子力学模型.并表示出能够精确求解的局域势模型的一个简单非局域的表示形式,精确地得到能量本征函数和本征值.     

类Quesne环状球谐振子势场中的赝自旋对称性

提出了一种新的类Quesne环状球谐振子势,应用二分量方法求解1/2-自旋粒子满足的Dirac方程, Dirac哈密顿量由标量和矢量类Quesne环状球谐振子势构成.在Σ=S(r)+V(r)=0的条件下,得到了Dirac旋量波函数下分量的束缚态解和能谱方程, 显示出类Quesne环状球谐振子势场中的赝自旋对称性.讨论了束缚态波函数和能谱方程的有关性质. 关键词： 类Quesne环状球谐振子势 Dirac方程 赝自旋对称性 束缚态     

双环形Coulomb势Schrdinger方程束缚态的精确解(英文)

双环形Coulomb势是指在氢原子势外面再加上一个双环形平方反比势,该模型势是在讨论类似于苯环分子结构的基础上提出的,该模型势在分子和原子物理中有着广泛的应用.本文研究了双环形Coulomb势Schr dinger方程的束缚态精确解,所采用的方法是首先对双环形Coulomb势的Schr dinger方程在球坐标系中进行分离变量,得到相应的角向方程和径向方程;证明双环形Coulomb势在角向和径向具有超对称性和形不变性;根据超对称性和形不变性的性质,获得了角动量量子化条件和束缚态的能谱方程,并将归一化角向波函数用Jacobi多项式表示,将归一化径向波函数用Laguerre多项式函数表示.体系的波函数和束缚态能谱性质由三个量子数n、m和s及势参数,αa和b描述.本文说明量子物理中一些具有对称性的非中心势有精确解,用超对称性和形不变性方法还可以讨论其他形式的非中心势.     

双环形Coulomb势Schroedinger方程束缚态的精确解

双环形Coulomb势是指在氢原子势外面再加上一个双环形平方反比势。该模型势是在讨论类似于苯环分子结构的基础上提出的，该模型势在分子和原子物理中有着广泛的应用．本文研究了双环形Coulomb势Schroedinger方程的束缚态精确解，所采用的方法是首先对双环形Coulomb势的Schroedinger方程在球坐标系中进行分离变量，得到相应的角向方程和径向方程；证明双环形Coulomb势在角向和径向具有超对称性和形不变性；根据超对称性和形不变性的性质，获得了角动量量子化条件和束缚态的能谱方程，并将归一化角向波函数用Jacobi多项式表示，将归一化径向波函数用Laguerre多项式函数表示．体系的波函数和束缚态能谱性质由三个量子数n、m和s及势参数a，a和b描述．本文说明量子物理中一些具有对称性的非中心势有精确解．用超对称性和形不变性方法还可以讨论其他形式的非中心势．     

Singularity Theorems and Their Consequences

A detailed study of the singularity theorems is presented. I discuss the plausibility and reasonability of their hypotheses, the applicability and implications of the theorems, as well as the theorems themselves. The consequences usually extracted from them, some of them without the necessary rigour, are widely and carefully analysed with many clarifying examples and alternative views.     

AC transport and magnetic characterisation of multifilamentary Ag-BSCCO(2223) tapes with different filament arrangements

AC losses in multifilamentary tapes depend on various parameters. Among them, geometrical factors such as overall tape width and thickness as well as the precise arrangement of the filaments are expected to have an important influence. Several theoretical models describe this dependency. In order to study these geometrical effects experimentally, we prepared a series of Bi(2223)/Ag tapes with gradually changing filament arrangements and tape aspect ratio, and characterised them by AC transport and magnetic measurements. The results are compared to model predictions.     

Short Time Domain and Double Resonance Techniques in Electron Spin Resonance Spectroscopy

Abstract

In recent years improvements in technology have increased the amount of information obtainable from, and have broadened the areas of application of, electron spin resonance spectroscopy. Some of the techniques that have found wide use in recent years, such as pulse saturation relaxation time measurements, ENDOR and ELDOR, were originally discovered many years ago while others, such as saturation transfer spectroscopy and nanosecond time resolved techniques, are based upon more recent developments. In this review we will survey a number of these techniques, we will explain what they are and what we can learn from them, we will describe some of the spectrometer systems that are required for using them, and we will cite many representative articles which provide further details about them.     

Normal Forms of Unknotted Ribbons and DNA

We study a certain class of unknotted smooth embeddings of ribbons (i.e., surfaces diffeomorphic to S¹×[?1,1]) in Euclidean space R³ (unknotted means that the midline of the ribbon is the unknot). Studying them from the mathematical point of view, we classify them. Regarding them as ideal physical objects with certain properties, we study their behavior under natural conditions. Finally, we discuss the eventual relationship of our models with DNA, RNA, and other long molecules appearing in biophysics.     

Some New Properties of Quantum Correlations

Quantum coherence measures the correlation between different measurement results in a single-system, while entanglement and quantum discord measure the correlation among different subsystems in a multipartite system. In this paper, we focus on the relative entropy form of them, and obtain three new properties of them as follows: 1) General forms of maximally coherent states for the relative entropy coherence, 2) Linear monogamy of the relative entropy entanglement, and 3) Subadditivity of quantum discord. Here, the linear monogamy is defined as there is a small constant as the upper bound on the sum of the relative entropy entanglement in subsystems.     

Behaviour of some non-linear optical powdered organic materials

Optical second-harmonic generation has been observed in several organic compounds with appreciable intensity. One of them, p-nitrophenylhydrazine, appears as good as frequency generator as m-nitroaniline.     

Statistical PMD and PDL effects emulator based on polarization maintaining optical fiber segments

Low cost statistical PMD/PDL emulator is presented. The emulator was initially designed as a classical PMD emulator. But PDL measurements of the designed emulator show that it can be also used as statistical PDL emulator. The emulator was constructed by concatenating 15 highly birefringence optical fiber segments and randomly varying the mode coupling between them, by rotating the polarization state between them. The achieved numerical and experimental results show that the designed emulator can mimic the polarization effects (PMD and PDL) of a real modern optical fiber link.     

Electronic structure and properties of NbS2 and TiS2 low dimensional structures

Transition metal dichalcogenides have a laminar structure, weakly bound through van der Waals interactions. Due to their technological applications in catalytic processes the bulk structure of many of them has been widely studied in the last 30 years. Some of them, such as NbTe₂ and TiSe₂, show superconductivity and have been, therefore, the subject of intense study. Novoselov et al. (2005 [1]) achieved to isolate not only graphene but also other bidimensional crystals, among them layers of some dichalcogenides. These bidimensional crystals preserve their monocrystallinity under normal ambient conditions, keeping the crystal structure of the bulk. In this contribution we calculate the magnetic and electronic properties of 2D layers of NbS₂ (non-magnetic metal in 3D) and TiS₂ (non-magnetic semimetal in 3D) as well as quasi 1D chains cut out from these layers.     

连续表面微透镜列阵元件检测

系统分析了连续表面微透镜列阵的几何参量和光学性能的检测方法和评价标准,针对典型的折射型聚焦列阵元件,给出其结构尺寸及光学性能的测试结果,两者结果一致.从而建立了一套通过测试元件的几何参量、加工误差及光学性能指标来综合评估微光学元件性能的方法.     

局域密度近似理论的适用范围及其理论证明

在电子密度中,可以假定存在一种能产生交换相关能的非局域空穴。通过该假定可将存在于局域密度理论中的电子自相互作用消除。由这种交换相关能所导出的非局域电子密度势具有两方面的作用:一方面会影响到由空穴产生的静电势;另一方面当空穴的大小和形状随其密度变化而引起能量变化时,它也会影响到描述这些变化的项。迄今为止,所有以往曾研究过此问题的国外学者都只考虑了前一方面的影响而忽略后一方面的作用。本文对包含这些项所引起的各种效应进行了全面而严格的检验,并采用了局域近似或完全忽略;若完全忽略会产生各种各样的无序波函数。本文证明对这些项可进行一般的局域估价,这种方法较之于精确处理要简便得多。 关键词：