Fidelity between Gaussian mixed states with quantum state quadrature variances  

作　　者：张海龙 周淳 史建红 鲍皖苏 

机构地区：[1]Zhengzhou Information Science and Technology Institute, Zhengzhou 450004, China [2]Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China [3]Science and Technology on Information Assurance Laboratory, Beijing 100071, China

出　　处：《Chinese Physics B》2016年第4期57-62,共6页中国物理B（英文版）

基　　金：supported by the National Basic Research Program of China(Grant No.2013CB338002);the Foundation of Science and Technology on Information Assurance Laboratory(Grant No.KJ-14-001)

摘　　要：In this paper, from the original definition of fidelity in a pure state, we first give a well-defined expansion fidelity between two Gaussian mixed states. It is related to the variances of output and input states in quantum information pro- cessing. It is convenient to quantify the quantum teleportation （quantum clone） experiment since the variances of the input （output） state are measurable. Furthermore, we also give a conclusion that the fidelity of a pure input state is smaller than the fidelity of a mixed input state in the same quantum information processing.In this paper, from the original definition of fidelity in a pure state, we first give a well-defined expansion fidelity between two Gaussian mixed states. It is related to the variances of output and input states in quantum information pro- cessing. It is convenient to quantify the quantum teleportation （quantum clone） experiment since the variances of the input （output） state are measurable. Furthermore, we also give a conclusion that the fidelity of a pure input state is smaller than the fidelity of a mixed input state in the same quantum information processing.

关 键 词：FIDELITY mixed state quantum clone quantum information processing 

分 类 号：O413[理学—理论物理]