Effect of excess noise on continuous variable entanglement sudden death and Gaussian quantum discord

作     者：苏晓龙 

作者机构：State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-Electronics Shanxi University 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2013年第22卷第8期

页      面：269-273页

核心收录：

学科分类：070207[理学-光学] 07[理学] 08[工学] 0803[工学-光学工程] 0702[理学-物理学] 

基　　金：supported by the National Basic Research Program of China(Grant No.2010CB923103) the National Natural Science Foundation of China(GrantNos.11174188 and 61121064) the Fund from the Shanxi Scholarship Council of China(Grant No.2012-010) 

主　　题：continuous variable entanglement quantum key distribution 

摘      要：A symmetric two-mode Gaussian entangled state is used to investigate the effect of excess noise on entanglement sudden death and Gaussian quantum discord with continuous variables. The results show that the excess noise in the channel can lead to entanglement sudden death of a symmetric two-mode Gaussian entangled state, while Gaussian quantum discord never vanishes. As a practical application, the security of a quantum key distribution （QKD） scheme based on a symmetric two-mode Gaussian entangled state against collective Gaussian attacks is analyzed. The calculation results show that the secret key cannot be distilled when entanglement vanishes and only quantum discord exists in such a QKD scheme.