单-双模组合压缩热态的纠缠性质及在量子隐形传态中的应用  

Entanglement of one- and two-mode combination squeezed thermal states and its application in quantum teleportation

作　　者：刘世右 郑凯敏 贾芳[1] 胡利云[1] 谢芳森[1] 

机构地区：[1]江西师范大学物理与通信电子学院,南昌330022

出　　处：《物理学报》2014年第14期55-63,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11264018);江西省自然科学基金(批准号:20132BAB212006);江西省教育厅科技项目(批准号:GJJ14274)资助的课题~~

摘　　要：基于单-双模组合压缩真空态一定范围内能够获得压缩增强的效果,引入单-双模组合压缩热态(DSMST),讨论其纠缠性质.利用Weyl编序算符在相似变换下的不变性,简洁方便地导出了DSMST的纠缠度-负对数值,并给出了当热效应存在时保持纠缠的条件.研究表明:与通常的双模压缩态相比,随着参数的增加,DSMST的纠缠度增加.作为DSMST的应用,利用其实现相干态的量子隐形传输.结果表明:不同于纠缠度随压缩参数增加,保真度获得改善是有条件的,该条件恰好就是一正交分量涨落出现压缩增强的参数区域.此外,解析推导了有效隐形传输保真度(>1/2)的条件.In view of the fact that one- and two-mode combination squeezed vacuum states may exhibit stronger squeezing in a certain range, we introduce one- and two-mode combination squeezed thermal states（OTCSTS） and investigate the property of entanglement in detail. Using the remarkable property of Weyl ordering, i.e., the order-invariance of Weyl ordered operator under similar transformations, we conveniently derive the analytical expression of entanglement degree-logarithmic negativity, and then present the condition of keeping entanglement for these squeezed thermal states.It is found that the OTCSTS possesses higher entanglement than the usual two-mode squeezed thermal states for any non-zero squeezing parameter. As an application, the quantum teleportation for coherent state is considered by using the OTCSTS as an entangled channel. It is shown that the teleportation fidelity can only be enhanced within a certain range of parameters, which is just the same as the condition of exhibiting stronger squeezing in one quadrature. In addition, the condition of realizing effective quantum teleportation（＆gt; 1/2） is obtained analytically.

关 键 词：单-双模组合压缩热态 WIGNER函数 纠缠 量子隐形传态 

分 类 号：O413.1[理学—理论物理]