【作者】 邹红梅；

【导师】 方卯发；

【作者基本信息】 湖南师范大学 ， 理论物理， 2007， 硕士

【摘要】 量子纠缠现象是量子力学不同于经典物理最奇特、最不可思议的特征。由于量子纠缠态特殊的物理性质,使量子信息具有经典信息所没有的许多新的特征,同时量子纠缠态也为量子信息传输和量子信息处理提供了新的物理资源,研究量子纠缠态及其在量子信息科学中的应用,具有非常重要的意义和价值。本文主要研究两二能级原子系统的量子纠缠。全文共分为四章。第一章介绍量子纠缠的基本理论。简述了量子纠缠态的定义,EPR佯谬和Bell不等式,给出了几类常见的量子纠缠态;简单介绍了量子纠缠的几种量度方法以及几种主要的量子纠缠操纵;最后简述了本文的工作。第二章研究两个部分纠缠二能级原子与单模真空场相互作用的量子纠缠。利用量子约化熵研究了两部分纠缠二能级原子与单模真空场之间的量子纠缠;利用量子相对熵研究了两部分纠缠二能级原子之间的量子纠缠;讨论了原子偶极-偶极相互作用对系统量子纠缠的影响。我们发现系统呈现出周期性的量子纠缠行为,量子纠缠的大小与周期依赖于原子之间的偶极-偶极相互作用。选取适当的系统参数和相互作用时间,可以制备原子-场最大纠缠态与原子-原子最大纠缠态。第三章研究在强经典场驱动下单模腔场中两二能级原子系统的量子纠缠。结果表明:初始制备在基态的两二能级原子系统在单模腔场(大失谐)和强经典场的共同作用下能产生量子纠缠,量子纠缠呈现周期性的变化,周期大小只与腔场有关;初始制备在最大纠缠态的两二能级原子系统,在单模腔场(大失谐)和强经典场的共同作用下能很好地保持原子系统的最大纠缠度。通过选择适当的参数条件和相互作用时间,可以制备出不同形式的两二能级原子最大纠缠态。第四章对全文进行了总结与展望。更多还原

【Abstract】 Quantum entanglement is the most inconceivable characteristic of quantum mechanics different from the classical physics.The quantum entanglement state has the special physical property so that the quantum infbrmation has many new characteristics different from the classical information:and the quantum entanglement state has also been viewed as a new physical resource of quantum information transmission and quantum information processing.Research on the quantum entanglement state and its application in the quantum information science has importantly significant and valuable.The quantum entanglement of two two-level atoms is mainly studied in this article.The whole thesis consists of four chapters.In chapterⅠ,the basic theory of quantum entanglement is presented. Firstly,the definition and properties of the quantum entangled states are introduced. The several kinds of quantum entangled states are given.Secondly, the measurement of the degree of quantum entanglement and manipulation of quantum entanglement are discussed.Finally,the main content of the article is briefly provided.In chapterⅡ.the quantum entanglement of two partially entangled twolevel atoms interacting with a single mode vacuum field is investigated.The quantum entanglement between two partially entangled two-level atoms and the vacuum field is explored by using the quantum reduced entropy,and one between two two-level atoms is studied by using the quantum relative entropy. The influences of the atomic dipole-dipole interaction intensity on the quantum entanglement of the system are also discussed.The results show that:the system exhibits periodic quantum entanglement dynamics,and the magnitude and the period of quantum entanglement depends on the atomic dipole-dipole interaction.The atom-field maximal quantum entanglement state and atomatom maximal entanglement state can be prepared by selecting appropriate system parameters and the interaction time.In chapterⅢ,the quantum entanglement of two two-level atoms simul- taneously interacting with a single-mode cavity field and droven by a strong classical field is investigated.The results show that With the large detuning and the strong driving,field,the quantum entanglement between two two-level atoms which,are initially prepared in the ground states is generated.The atomic system exhibits periodic quantum entanglement dynamics,and the period of quantum entanglement only depends on the single-mode cavity field. With the large detuning and the strong driving field,the quantum entanglement degree between two two-level atoms which are initially prepared in the maximal entanglement states is maintained well.The different maximal quantum entanglement state of the atom-atom can be prepared by selecting appropriate system parameters and the interaction time.In chapterⅣ,the summarization and the hope are presented.更多还原