基于多模压缩系数对非对称EPR态的纠缠结构判定

多体连续变量纠缠态是量子信息中非常重要的核心资源.非对称EPR态是实验上可以产生的一类重要的多体连续变量纠缠态.我们利用多模压缩系数发展的判据微观地对四模非对称EPR态的纠缠结构进行了判定.研究表明压缩参数r取0到1时，四模非对称EPR态所有划分方式的子系统间都存在纠缠，且纠缠程度随着压缩参数r增大而增大.同时，对A,B模式上分别增加信道损耗时，发现四模非对称EPR态所有划分方式的子系统间的纠缠程度会减弱，但是依然存在纠缠.     

EPR纠缠对的测量理论

章利用量子力学的测量理论,将连续变量EPR纠缠态与分离变量的EPR纠缠态的描述很好的结合起来。说明了在对双模压真空态的其中一个模进行正交位相振幅分量的测量过程中,可迫使另一模制备到其相应的正交位相振幅分量的本征态上即单模压缩真空态。     

两体纠缠态的应用

给出了两体纠缠态的性质与产生方法,用正规乘积技术得到了两体与三体连续变量纠缠态在坐标表象下的分解形式,展现了它们的完全性与正交归一性,提出了用三个两体纠缠态作为通道传榆一种连续变量三体纠缠态的方案.     

基于多波混频的三体连续变量纠缠

基于多波混频参数相互作用,研究了一个五能级原子系综中的三体连续变量纠缠.其中,两个光场通过一个双通道Raman跃迁,以和模的形式组合成一个联合模与原子相互作用,这个联合模因外加相干场与第三个腔场介于混频参数相互作用,导致了3个腔场正交算符的方差和满足三体连续变量纠缠有效判据,从而实现了稳态三体连续变量纠缠.     

Ising模型的腔QED模拟和最大纠缠态的存储以及四体纠缠态的产生

提出了在腔中模拟Ising模型、存储最大纠缠态和产生的四体量子纠缠态的简单方案．单模腔中的两个二能级原子受到强经典驱动场的作用,在大失谐条件下,系统的有效哈密顿量和标准的Ising模型相同．这一系统可使初始处于Bell基的两原子始终处于最大纠缠态,其中两个Bell基是系统的本征态;另外两个Bell基仅需要对其中一个原子作局域操作,仍然保持最大纠缠态．这个系统与腔模和环境没有相互作用,可长时间存储原子纠缠态而不会发生退相干．此外,利用该模型可以提出制备四体纠缠态的方案,即由现存的两Bell态可以一步得到四体真正纠缠态;存在两个GHZ态的条件下,可以很容易得到四粒子的标准Cluster态,在该机制下制备四粒子标准Cluster态的成功几率为1．     

用正交压缩态光场产生连续变量类GHZ和类Cluster四组分纠缠态

设计了一种有效的连续变量类 GHZ和类Cluster四组分纠缠态光场的实验产生系统. 从理论上证明, 利用一对非简并光学参量放大器所产生的4个正交振幅和正交位相压缩态光场, 经由不同位相关系的线性光学变换, 可以按要求产生两种不同类型的四组分纠缠态. 推出了四组分Cluster态的完全不可分判据, 并计算了连续变量四组分纠缠态关联方差对光场初始压缩度、系统传输效率及零差探测效率的参量依赖关系.     

连续变量系统中准对称多模高斯态的纠缠

基于现今连续变量系统中高斯态纠缠的一些研究成果,利用负性对数为纠缠度量来讨论一个准对称的N模高斯态的纠缠问题.以一个准对称八模高斯态为例,寻找八模高斯态和与其对应的两模高斯态共变矩阵参数之间的解析关系.研究发现在多模高斯态对应两模高斯态的方案中由于省略了多模高斯态辛本征值的部分信息,导致这种方案虽然可以使多模高斯态对应为一个两模高斯态,但是这种对应关系不是唯一的,一个两模高斯态可以对应很多不同的多模高斯态,而且这些高斯态拥有着相同的纠缠信息.通过寻找八模高斯态与两模高斯态参数间的解析关系,研究发现只要确定辛本征值就能得到八模高斯态和两模高斯态参数之间的解析关系,按照这个思路可以得到N模高斯态与两模高斯态参数间的解析关系.     

用正交压缩态光场产生连续变量类GHZ和类Cluster四组分纠缠态

设计了一种有效的连续变量类 GHZ和类Cluster四组分纠缠态光场的实验产生系统. 从理论上证明, 利用一对非简并光学参量放大器所产生的4个正交振幅和正交位相压缩态光场, 经由不同位相关系的线性光学变换, 可以按要求产生两种不同类型的四组分纠缠态. 推出了四组分Cluster态的完全不可分判据, 并计算了连续变量四组分纠缠态关联方差对光场初始压缩度、系统传输效率及零差探测效率的参量依赖关系.     

利用推广的Jaynes-Cummings模型存储最大纠缠态及纠缠提纯

提出了利用推广的Jaynes—Cummings（J-C）模型存储最大纠缠态,在此模型中原子与腔模和环境没有相互作用,因此可长时间存储原子纠缠态而不会发生退相干。此外,利用此模型可对处于非最大纠缠两原子态进行纠缠提纯。     

量子隐形传送两体任意态的真实四体纠缠通道方案

提出了一种用真实的四体最大纠缠态实现两体任意量子态的隐形传送方案,构建了16个正交完备基矢,这些基矢都是真实的四体纠缠态,即不能写成直积的形式.该方案揭示了一种四体纠缠态的某种特殊纠缠属性,并表明从某种意义上来讲,还可以从这样的一个四体纠缠态中提取出2个Bell态的纠缠.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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