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Experimental purification of two-atom entanglement



Rainer Reichle, Dietrich G. Leibfried, Emanuel H. Knill, Joseph W. Britton, Brad R. Blakestad, John D. Jost, C. Langer, R Ozeri, Signe Seidelin, David J. Wineland


Entanglement is one of the most counterintuitive features of quantum mechanics. It is a necessary resource for quantum communication and quantum information processing. Entanglement established between different locations enables private communication and quantum teleportation, and facilitates quantum information processing. Such distributed entanglement is established by preparing an entangled pair of quantum particles in one location and coherently transporting one member of the pair to another location. Unavoidable decoherence during transport reduces the quality (fidelity) of the entanglement. To improve this fidelity, Bennett et al. proposed an "entanglement purification'' protocol. This protocol uses separate quantum operations in each location and classical communication to distill high fidelity entangled pairs from lower fidelity ones. Its many applications render entanglement purification one of the quintessential techniques of quantum information processing. Several proof-of-principle experiments purifying entangled photon pairs have been carried out. However, these experiments obtained purified pairs with low probability of success and required destruction of the entangled pairs, making them unavailable for further processing. Here we report the implementation of efficient and non-destructive entanglement purification with atomic quantum bits. Two noisy entangled pairs were created and purified into one higher fidelity pair available for further use. Success probabilities were above 35 %.


entanglement purification, laser manipulation, quantum information processing, trapped ions


Reichle, R. , Leibfried, D. , Knill, E. , Britton, J. , Blakestad, B. , Jost, J. , Langer, C. , Ozeri, R. , Seidelin, S. and Wineland, D. (2006), Experimental purification of two-atom entanglement, Nature, [online], (Accessed June 14, 2024)


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Created October 19, 2006, Updated January 27, 2020