非最大量子糾纏態(tài)下的量子密集編碼

摘  要

2O世紀(jì)前半葉，自然學(xué)科誕生了最具影響力的兩門學(xué)科，量子力學(xué)和信息學(xué)。前者成為目前研究微觀粒子運動規(guī)律離不開的理論基礎(chǔ)，使人類對自然界的認(rèn)識發(fā)生了里程碑的突破，它解釋和預(yù)言了大量奇妙的物理現(xiàn)象，如微觀粒子的波粒二象性、隧道效應(yīng)和糾纏現(xiàn)象等等。利用量子力學(xué)原理，不僅解釋了原子結(jié)構(gòu)、化學(xué)鍵、超導(dǎo)現(xiàn)象、基本粒子的產(chǎn)生和湮滅等重要物理問題，而且也促成了現(xiàn)代
微電子技術(shù)、激光技術(shù)和核能利用技術(shù)等的出現(xiàn)。而后者已明顯地改變了人們的生產(chǎn)和生活方式，提高了工作效率和生活質(zhì)量。2O世紀(jì)末葉，它們交匯在一起，產(chǎn)生了一門新的交叉學(xué)科——量子信息學(xué)。鑒于量子信息學(xué)研究與應(yīng)用的巨大潛力，特別是關(guān)系到國家信息安全的重大問題，許多國家投人了大量人力物力開展相關(guān)方面的研究工作，促進了這一學(xué)科在誕生后的1O多年時間內(nèi)飛速發(fā)展。更是由于它具有經(jīng)典信息無法比擬的優(yōu)勢和前景，近年來受到廣泛關(guān)注和發(fā)展。本文簡要說明了量子信息的理論基礎(chǔ)，和量子信息學(xué)的核心部分即量子糾纏態(tài)的幾個基礎(chǔ)定義，著重介紹了非最大糾纏態(tài)下的量子密集編碼，同時也闡述了腔QED理論及是如何利用腔QED來實現(xiàn)非最大糾纏W態(tài)的。

關(guān)鍵詞：量子信息  量子糾纏  量子密集編碼  腔QED  非最大糾纏態(tài)

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  錄
                                                                       
前  言……………………………………………………………………4
一：量子信息基礎(chǔ)理論…………………………………………………4
二：糾纏態(tài)………………………………………………………………5
2.1:純態(tài)糾纏態(tài)……………………………………………………5
2.2:混合態(tài)糾纏態(tài)…………………………………………………6
2.3:糾纏度…………………………………………………………6
三:量子密集編碼………………………………………………………7
四：腔QED………………………………………………………………8
4.1:腔QED理論……………………………………………………8
4.2：原子腔場糾纏態(tài)的產(chǎn)生……………………………………10
4.3:非最大糾纏態(tài)W態(tài)的制備…………………………………11
4.4:一般三粒子非最大糾纏W態(tài)作為量子信道對單粒子疊加態(tài)的傳送………………………………………………………12
4.5:非最大糾纏態(tài)的概率密集編碼……………………………15
五：結(jié)論………………………………………………………………17
六：致謝………………………………………………………………17
七：參考文獻…………………………………………………………18
八：附錄………………………………………………………………19