Decoherence Induced by Spin Chain Environment

We study the decoherence process of an exact solvable model that consists of a central spin-1/2 coupling to the surrounding anisotropy spin-1/2 chain in transverse fields. The Loschrnidt echo is calculated to study the character of decoherence with different degree of anisotropy. Our results show that the degree of anisotropy γ greatly affects the decoherence process of the central spin-system when the spin chain is in weak transverse fields, but it gives weak effect in the strong transverse field. The decoherence process of the central system changed dramatically along the line of the critical points, and this may be explained as the reflection of quantum phase transitions.     

一个电磁感应佯谬及其理论分析

提出一个令人困惑的电磁感应问题，并运用电磁学理论对其进行了详尽的理论分析。     

基于频域方法的三维物体分层重现

基于频域方法实现了数字记录和再现三维物体离轴全息图.通过频谱对应关系求得各个面的频谱分布,使用数字滤波方法,成功地消除了零级衍射和共轭像;通过改变再现距离,分别获取了三维物体各个截面的再现像.     

~ Transform Demonstration of Dark Soliton Solutions Found by Inverse Scattering

One of the basic problems about the inverse scattering transform for solving a completely integrable nonlinear evolutions equation is to demonstrate that the Jost solutions obtained from the inverse scattering equations of Cauchy integral satisfy the Lax equations. Such a basic problem still exists in the procedure of deriving the dark soliton solutions of the NLS equation in normal dispersion with non-vanishing boundary conditions through the inverse scattering transform. In this paper, a pair of Jost solutions with same analytic properties are composed to be a 2 × 2 matrix and then another pair are introduced to be its right inverse confirmed by the Liouville theorem. As they are both 2 × 2 matrices, the right inverse should be the left inverse too, based upon which it is not difficult to show that these Jost solutions satisfy both the first and second Lax equations. As a result of compatibility condition, the dark soliton solutions definitely satisfy the NLS equation in normal dispersion with non-vanishing boundary conditions.     

从高考试题的改变看等效变换的应用

 等效变换并不是一个新鲜名词,但是它的应用却有许多新花样,它是考查学生综合素质和能力的一种有效途径。教育部在《普通高校招生制度改革方案》中提出了“三个有助于”和“四个方面”的总体改革方案,总体上将更加注重对考生能力和素质的考查。分析2000年各地及全国高考理科综合能力测试卷,我们不难发现,等效思维在其中的作用。而等效变换的思路只有在对物理原理理解透彻的基础上,才能灵活运用,它是考查学生综合素质和能力的一种有效途径。     

1.5μm波段基于级联二阶非线性的铌酸锂光波导全光波长变换的理论分析

研究了基于级联二阶非线性的铌酸锂波导全光波长变换器的特性.首先从耦合模方程出发,比较了数值分析结果与小信号近似分析的结果.其次在数值分析基础上,分析了铌酸锂晶体的温度变化导致相应基频光波波长与极化反转光栅周期的变化关系.最后分析了在不同相互作用长度下,转换的光波功率与有效基频光波波长带宽、温度调谐带宽、极化反转光栅周期带宽等关系,以对全光波长变换器件进行优化设计 关键词： 级联二阶非线性 波长变换 准位相匹配 铌酸锂光波导     

威灵仙及其伪品的FTIR法直接鉴定

采用傅里叶变换红外光谱（FTIR）法，借助OMNI采样器直接测定了中药材威灵仙及其伪品华东菝葜、山木通和毛柱铁线莲的红外光谱，结果发现正伪品的红餐光谱差别较大。因此FTIR法可以直接、快速、准确地对威灵仙与其伪品华东菝葜、山木通和毛柱铁线莲进行区别鉴定。     

遥感傅里叶变换红外光谱的大气层析技术

遥感傅里叶变换红外光谱层析技术是一项新的气体分析技术，它可用于构造气体浓度峰图形，定量分析工业污染气体总释放量等方面，随着算法的不断优化，在重构气体在空间的分布方面，遥感傅里叶变换红外光谱层析技术正在不断成长。     

类Kerr介质中双模SU(1,1)相干态场与Λ型三能级原子相互作用的量子统计性质

导出了类Kerr介质中双模SU(1,1)相干态场与Λ型三能级原子相互作用系统的态函数,研究了Kerr效应对Λ型三能级原子布居概率、双模SU(1,1)相干态场的互关联函数、Cauchy-Schwartz不等式及二阶相干度的影响.结果表明:Kerr效应使原子与光场的耦合减弱,原子布居的崩塌与复苏的周期缩短;在初始光场较弱和较强两种情况下,类Kerr介质对双模SU(1,1)相干态场两模间的相关性、相关程度以及光子的聚束与反聚束效应产生的作用有明显的区别.     

晶格振动德拜模型的新思考

利用对德拜模式密度的修正入手，重新讨论了频率函数的热容量，得到了在高、低温极限与实验相符合的结论，该模型保留了德拜模型的优点，又对其不足之外进行了修正，同时给出了修正项的来源。