光晶格中偶极BEC偶极——偶极相互作用极限的讨论

在GP方程和离散Schrodinger方程的基础上,根据对光晶格中偶极玻色——爱因斯坦凝聚体(BEC)的调制不稳定性的研究,如果频率出现虚值,则光晶格中的偶极BEC将出现调制不稳定性,而偶极——偶极相互作用对光晶格中偶极BEC的非线性激发和稳定性有很大的影响。由于偶极——偶极相互作用可以通过外场很方便地进行调节,本文中,我们对光晶格中偶极BEC偶极——偶极相互作用的极限进行了必要的讨论,这可为实际应用中如何操控偶极BEC提供有用的信息。     

光晶格中双组分偶极BECs的临界振幅

在线性稳定性分析和离散非线性Schrdinger方程的基础上,对光晶格中双组分偶极玻色-爱因斯坦凝聚体(BECs)调制不稳定性的临界振幅进行了研究,得到了光晶格中双组分偶极BECs原子系统的激发谱和调制不稳定性的临界振幅及它们与在位相互作用和由偶极-偶极相互作用所导致的格点间BECs的相互作用之间的关系.结果显示,格点间BECs的相互作用对光晶格中双组分偶极BECs的调制不稳定性有很大的影响,这可为实际应用中如何操控双组分偶极BECs提供有用的信息.     

相干态光场与耦合双原子系统中光子的统计性质

采用全量子理论和数值计算方法求解了旋波近似下相干态光场与耦合双原子相互作用的系统波函数,分析了原子的初始状态和原子间偶极偶极相互作用Ω对光子统计性质的影响.数值计算结果显示:原子间偶极偶极相互作用Ω对光子的超泊松分布效应无明显影响,但崩塌-回复周期却随Ω的增大而减小,近似成反比关系;系统初始状态对光子的超泊松分布效应有明显影响,而对崩塌回复周期无影响.     

准一维偶极玻色-爱因斯坦凝聚体中的亮孤子

通过变分法分析,发现排斥短程相互作用的准一维BEC是不存在亮孤子的,但是当长程的偶极相互作用存在时,两者的相互影响导致了准一维BEC凝聚体中稳定的亮孤子的产生.另外,当偶极相互作用过大时,又会破坏孤子.     

光学晶格中一维偶极玻色气体的各向异性超流

文章研究了准一维光学晶格中的超冷玻色气体在偶板-偶极相互作用下的超流性质.通过解析分析发现,对于一维铬玻色原子气体,适当调节偶极原子的指向可以抑制超流的发生,在特定夹角处不存在超流.当接触作用与偶极相互作用可以相比拟时该效应最为明显,在实验上可以通过测量粒子流来验证该效应.     

偶极玻色-爱因斯坦凝聚体的稳定性分析

利用变分法,在给出三维简谐势阱的频率方位比后,考察处于该势阱中的偶极BEC凝聚体,我们发现偶极玻色-爱因斯坦凝聚体的稳定性由势阱的频率方位比、s-波散射长度、偶极相互作用强度和粒子数目等因素共同决定,当合适的参量给定后,NLSE总有亮孤子解存在,并可得到稳态与非稳态间的临界线.     

基于计算经典辐射功率的量子偶极-偶极相互作用求解

提出了一种通用的严格求解任意微纳结构中2个二能级“原子”间量子偶极-偶极相互作用的方法.量子偶极-偶极相互作用传输率用2个经典电偶极子同时存在时的辐射功率减去它们单独存在时的辐射功率来表达,辐射功率通过经典的时域有限差分方法获得.将该方法应用到偶极子处于真空和平板金属腔中的情况,其数值结果与解析结果符合得很好,验证了该方法的可行性.     

T-C模型中纠缠原子与相干态光场相互作用的场熵演化特性

利用全量子理论,研究了一对纠缠原子与相干态光场相互作用中场熵的演化特性.讨论了原子间偶极-偶极相互作用、光场强度与2原子纠缠度对场熵演化特性的影响.结果表明:原子间偶极-偶极相互作用强度增加使场熵的演化周期增大;初始光场强度增加,场熵平均值先增大后减小,振荡周期变大;场熵平均值随初始纠缠度增大反而减小,但振荡幅度随初始纠缠度增大而增大.     

偶极—偶极相互作用的探讨

本文用相关势近似方法阐明在增强拉曼光谱和电势调节红外光谱中观察到的偶极-偶极相互作用,特别是表现出来的强度转移和频率位移现象。     

两纠缠二能级原子在耗散环境中的纠缠动力学性质

耗散环境中量子纠缠动力学性质是实际量子信息处理的关键问题,本文研究了两个任意纠缠二能级原子与单模耗散环境中的相互作用的纠缠动力学。利用Wootters的共生纠缠度做度量工具,讨论了两纠缠原子间的纠缠动力学与偶极-偶极相互作用的依赖关系。结果表明:当忽略原子间的偶极-偶极相互作用时,系统呈现出周期为2π/姨6 g的纠缠动力学行为;当考虑原子间的偶极-偶极相互作用时,其振荡频率有所降低,及双原子系统纠缠度越难以衰减到零。原子间的偶极-偶极相互作用对抑制双原子激发态能量的衰变起着加强作用,从而对纠缠具有保持效应。     

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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