Local conversion of Greenberger-Horne-Zeilinger states to approximate W states

Author(s): P. Walther, K. J. Resch, A. Zeilinger

Journal: Physical Review Letters

Volume: 94

Page(s): 240501

Year: 2005

DOI Number: 10.1103/PhysRevLett.94.240501

Link: Link to publication


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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