Abstract Remote quantum-state discrimination is a critical step for the implementation of quantum communication network and distributed quantum computation. We present a protocol for remotely implementing the unambiguous discrimination between nonorthogonal states using quantum entanglements, local operations, and classical communications. This protocol consists of a remote generalized measurement described by a positive operator valued measurement (POVM). We explicitly construct the required remote POVM. The remote POVM can be realized by performing a nonlocal controlled-rotation operation on two spatially separated qubits, one is an ancillary qubit and the other is the qubit which is encoded by two nonorthogonal states to be distinguished, and a conventional local Von Neumann orthogonal measurement on the ancilla. The particular pair of states that can be remotely and unambiguously distinguished is specified by the state of the ancilla. The probability of successful discrimination is not optimal for all admissible pairs. However, for some subset it can be very close to an optimal value in an ordinary local POVM.
Received: 31 December 2006
Revised: 17 September 2007
Accepted manuscript online:
(Telecommunications: signal transmission and processing; communication satellites)
Fund: Project supported by the Natural
Science Foundation of Guangdong Province, China (Grant Nos 06029431
and 020127), and the Natural Science Foundation of
the Education Bureau of Guangdong Province, China (Grant No Z02069).
Cite this article:
Chen Li-Bing(陈立冰), Jin Rui-Bo(金锐博), and Lu Hong(路洪) Remote interactions on two distributed quantum systems: nonlocal unambiguous quantum-state discrimination 2008 Chin. Phys. B 17 778
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