Application of quantum algorithms to direct measurement of concurrence of a two-qubit pure state
Wang Hong-Fu(王洪福)a) and Zhang Shou(张寿)a)b)†
a Center for the Condensed-Matter Science and Technology, Harbin Institute of Technology, Harbin 150001, China; b Department of Physics, College of Science, Yanbian University, Yanji 133002, China
Abstract This paper proposes a method to measure directly the concurrence of an arbitrary two-qubit pure state based on a generalized Grover quantum iteration algorithm and a phase estimation algorithm. The concurrence can be calculated by applying quantum algorithms to two available copies of the bipartite system, and a final measurement on the auxiliary working qubits gives a better estimation of the concurrence. This method opens new prospects of entanglement measure by the application of quantum algorithms. The implementation of the protocol would be an important step toward quantum information processing and more complex entanglement measure of the finite-dimensional quantum system with an arbitrary number of qubits.
Received: 13 October 2008
Revised: 05 November 2008
Accepted manuscript online:
PACS:
03.67.Lx
(Quantum computation architectures and implementations)
(Entanglement measures, witnesses, and other characterizations)
Fund: Project supported by the National
Natural Science Foundation of
China (Grant No 60667001).
Cite this article:
Wang Hong-Fu(王洪福) and Zhang Shou(张寿) Application of quantum algorithms to direct measurement of concurrence of a two-qubit pure state 2009 Chin. Phys. B 18 2642
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