Entanglement Preserving in Quantum Copying of Three-Qubit Entangled State  

作　　者：TONG Zhao-Yang KUANG Le-Man 

机构地区：[1]Department of Physics, Hunan Normal University, Changsha 410081, China Department of Physics, Hunan Normal University, Changsha 410081, China

出　　处：《Communications in Theoretical Physics》2002年第11期541-546,共6页理论物理通讯（英文版）

基　　金：The project supported in part by the National Fundamental Research Program, National Natural Science Foundation of China, EYTFof the Educational Department of China, and Hunan Province STF

摘　　要：We study the degree to which quantum entanglement survives when a three-qubit entangled state iscopied by using local and non-local processes, respectively, and investigate iterating quantum copyingfor the three-qubitsystem. There may exist inter-three-qubit entanglement and inter-two-qubit entanglement for the three-qubit system.We show that both local and non-local copying processes degrade quantum entanglement in the three-particle systemdue to a residual correlation between the copied output and the copying machine. We also show that the inter-two-qubitentanglement is preserved better than the inter-three-qubit entanglement in the local cloning process. We find thatnon-local cloning is much more efficient than the local copying for broadcasting entanglement, and output state vianon-local cloning exhibits the fidelity better than local cloning.

关 键 词：ENTANGLED states  QUANTUM entanglement  QUANTUM COPYING 

分 类 号：O4[理学—物理]