Optimal Entanglement Concentration of the Greenberger-Horne-Zeilinger States in Quantum-dot and Micro-cavity Coupled System
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The distillation of the triplet Greenberger-Horne-Zeilinger (GHZ) state is demonstrated by using the entanglement concentrating process for the partially electron-spin-entangled systems. We designate an entanglement concentration protocol (ECP) in the quantum-dot (QD) and micro-cavity coupled systems based on the post-selection, from which the partially entangled state can be concentrated with an aid of the ancillary QD and single photon. This protocol can be repeated several rounds to get an optimal success probability. With the current technology, the maximally entangled electron spins can be achieved in the GHZ states after performing some suitable unitary operation locally for the long-distance quantum communications. The advantage is that during the whole process only the single photon needs to pass through the micro-cavity which increases the total success probability even if the cavity is imperfect in implementations.
KeywordsEntanglement Bell state Greenberger-Horne-Zeilinger state Entanglement distillation Quantum communications Quantum information