非最大量子纠缠态下的量子密集编码.doc

非最大量子纠缠态下的量子密集编码

摘  要

2O世纪前半叶，自然学科诞生了最具影响力的两门学科，量子力学和信息学。前者成为目前研究微观粒子运动规律离不开的理论基础，使人类对自然界的认识发生了里程碑的突破，它解释和预言了大量奇妙的物理现象，如微观粒子的波粒二象性、隧道效应和纠缠现象等等。利用量子力学原理，不仅解释了原子结构、化学键、超导现象、基本粒子的产生和湮灭等重要物理问题，而且也促成了现代
微电子技术、激光技术和核能利用技术等的出现。而后者已明显地改变了人们的生产和生活方式，提高了工作效率和生活质量。2O世纪末叶，它们交汇在一起，产生了一门新的交叉学科——量子信息学。鉴于量子信息学研究与应用的巨大潜力，特别是关系到国家信息安全的重大问题，许多国家投人了大量人力物力开展相关方面的研究工作，促进了这一学科在诞生后的1O多年时间内飞速发展。更是由于它具有经典信息无法比拟的优势和前景，近年来受到广泛关注和发展。本文简要说明了量子信息的理论基础，和量子信息学的核心部分即量子纠缠态的几个基础定义，着重介绍了非最大纠缠态下的量子密集编码，同时也阐述了腔QED理论及是如何利用腔QED来实现非最大纠缠W态的。

关键词：量子信息  量子纠缠  量子密集编码  腔QED  非最大纠缠态

ABSTRACT
In the first half of the 20th century, natural discipline was born of the most two influential disciplines, quantum mechanics and informatics. The former has been the theoretical foundation of studying microscopic particles motion rule of nature, and the breakthrough of human understanding of nature has occurred  milestone, quantum mechanics explained and predicted large wonderful physical phenomenas, such as microscopic particles wave-particle duality, tunnel effect and pester phenomenon and so on. It is not only explaining atomic structure, chemical bonds, superconducting phenomena, the basic particle of produce and annihilation, and other important physical problems, but also contributing to the emerge of modern Microelectronics technology, laser technology and nuclear power use technology by using quantum mechanics principle. While the latter has obviously changed people's production and life style, and improved the working efficiency and quality of life. In the 20th century page, they joined together to produce a new interdisciplinary -- quantum informatics. In view of the great potential of quantum informatics research and application, especially in relation to the major national information security problems, many countries  develop relevant research work by put into a lot of manpower resources and this promotes this subject to rapid development in the years after the birth of 1O duration. But also because it has incomparable advantages and prospect that a  classic information can not achieve, informatics gets the comprehensive attention and development in recent years. This paper briefly explains the basic theory of quantum information, and the core part of quantum informatics ,quantum entanglement's several basic definitions, lays its stress on the main quantum dense coding under the non-maximally entangled state , also expounds cavity QED theory and how to achieve the maximum cavity of entanglement W state by QED.

Keywords: Quantum information; quantum dense coding;
quantum entanglement; cavity QED; the non-maximally entangled state

                                目  录
                                                                       
前  言……………………………………………………………………4
一：量子信息基础理论…………………………………………………4
二：纠缠态………………………………………………………………5
2.1:纯态纠缠态……………………………………………………5
2.2:混合态纠缠态…………………………………………………6
2.3:纠缠度…………………………………………………………6
三:量子密集编码………………………………………………………7
四：腔QED………………………………………………………………8
4.1:腔QED理论……………………………………………………8
4.2：原子腔场纠缠态的产生……………………………………10
4.3:非最大纠缠态W态的制备…………………………………11
4.4:一般三粒子非最大纠缠W态作为量子信道对单粒子叠加态的传送………………………………………………………12
4.5:非最大纠缠态的概率密集编码……………………………15
五：结论………………………………………………………………17
六：致谢………………………………………………………………17
七：参考文献…………………………………………………………18
八：附录………………………………………………………………19