多粒子纠缠的制备和操纵

【作者】 张瑾；

【导师】 潘建伟； 杨涛；

【作者基本信息】 中国科学技术大学 ， 原子分子物理， 2007， 博士

【摘要】 量子纠缠态的制备和操纵是量子信息中重要的研究内容，纠缠态是量子通信和量子计算中的重要资源，比如量子隐形传态，one-way量子计算等，可以说实现量子信息的过程就是对量子态进行操纵的过程，而且它在检测量子力学基本理论方面也有着重要的意义。本论文的主要内容就是关于多粒子纠缠态的制备，以及利用多粒子纠缠态对量子力学基本理论进行检验。在本文中我们提出了制备多粒子纠缠态的理论方案，介绍了我们在实验上实现的六光子纠缠态的制备，而且还通过实验上制备四光子混态首次对混态情况下利用无不等式的Bell定理对量子力学的非定域性进行了实验检验。本论文的主要内容和结构如下：第一章为绪论，对量子信息学的主要内容进行了简单介绍，阐述了量子纠缠的定义，判定以及纠缠度量的问题。第二章首先介绍量子光学中的一些基本技术手段，包括自发参量下转换，以及光学实验中常用到的一些光学器件，然后提出利用光学方法制备五光子图态的理论方案，最后详细介绍我们在实验上实现的六光子纠缠态制备。第三章介绍了腔量子电动力学系统中常见的原子和腔场的共振和非共振相互作用，并进一步提出利用原子和腔场非共振相互作用制备五原子纠缠图态的理论方案。第四章首先介绍了用来检验量子力学和定域实在论矛盾冲突的Bell不等式，CHSH不等式以及无不等式的Bell定理——GHZ定理，然后介绍我们通过制备四光子混态利用无不等式的Bell定理来验证量子力学非定域性的理论方案和实验结果。第五章是对研究工作的总结和进一步的展望。更多还原

【Abstract】 Preparation and manipulation of quantum entangled states lies at the heart of the quantum information. First, entangled states are important resources for quantum communication and quantum computation such as quantum teleportation, quantum one-way computation and so on. The process of performing quantum information tasks even can be regarded as the process of manipulation of entangled states. Second, they play a crucial role in testing the foundmental principles of quantum mechanics. This thesis is mainly about preparation of the multiparticle entangled states and test of the conflict between quantum mechanics and local realism. In this thesis we propose schemes for generation of multiparticle entangled states and report the experimental realization of six-photon entangled states and the experimental test of the nonlocality of quantum mechanics based on the four-photon mixed state.The thesis is structured as follows:Chapter No. 1 is the exordium. We simply introduce the main content of quantum information theory and elaborate notion, separability and measure of entanglement.In chapter No.2, we firstly introduce some basic technique of quantum optics, including spontaneous parametric down conversion and some optical elements, then, we propose schemes for preparation of five-photon graph states, lastly, we report the experimental realization of six-photon entangled states.In chapter No. 3, we introduce resonant and nonresonant interactions beween the atoms and cavities in cavity electrodynamics and propose schemes for generating five-atom graph states via cavity electrodynamics.In chapter No.4, we firstly introduce Bell’s theory, CHSH inequality and GHZ contradiction, and then, we report the experimental test of all-verus-nothing violation of local realism based on the four-photon mixed state.Chapter No.5 is conclusion and future outlook.更多还原