Entanglement concentration for multi-particle partially entangled W state using nitrogen vacancy center and microtoroidal resonator system

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• 作者：Ling-yan He^a ; Cong Cao^a ; Chuan Wang^b ; ^{chuan-wang03@mails.tsinghua.edu.cn} ; ^{wangchuan@bupt.edu.cn}
• 关键词：Entanglement concentration ; N-V center ; W state ; Parity-check measurement
• 刊名：Optics Communications
• 出版年：2013
• 出版时间：1 July, 2013
• 年：2013
• 卷：298-299
• 期：Complete
• 页码：260-266
• 全文大小：472 K

文摘

In this paper, we present an efficient entanglement concentration protocol (ECP) for N spatially separated nitrogen-vacancy (N-V) centers coupled to microtoroidal resonators in a partially entangled W state. The robustness of W-type entanglement contrasts strongly with the Greenberger-Horne-Zeilinger (GHZ) state which is fully separable after loss of one qubit. We construct the parity-check gate by introducing an auxiliary N-V center in microcavity and a single photon. Based on the parity-check measurement and local operations, the remote parities can distill a maximally entangled W state from a partially entangled state with a certain success probability. By iterating the concentration process several times, the present ECP can obtain an optimal yield. With its robustness and scalability, the present ECP for entangled N-V center ensembles can be widely applied to quantum repeaters and long-distance quantum communications.