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Local Conversion of Greenberger-Horne-Zeilinger States to Approximate W States

P. Walther·K. J. Resch·A. Zeilinger
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Abstract

Genuine 3-qubit entanglement comes in two different inconvertible types represented by the Greenberger-Horne-Zeilinger (GHZ) state and the W state. We describe a specific method based on local positive operator valued measures and classical communication that can convert the ideal N-qubit GHZ state to a state arbitrarily close to the ideal N-qubit W state. We then experimentally implement this scheme in the 3-qubit case and characterize the input and the final state using 3-photon quantum state tomography.

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P. Walther, K. J. Resch, A. Zeilinger. 2005-06-22. Local Conversion of Greenberger-Horne-Zeilinger States to Approximate W States. https://doi.org/10.1103/physrevlett.94.240501

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