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Phys. Rev. Lett. 103, 210501 (2009) [4 pages]

Perfect Distinguishability of Quantum Operations

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Runyao Duan*, Yuan Feng, and Mingsheng Ying
State Key Laboratory of Intelligent Technology and Systems, Tsinghua National Laboratory for Information Science and Technology, Department of Computer Science and Technology, Tsinghua University, Beijing 100084, China and Centre for Quantum Computation and Intelligent Systems (QCIS), Faculty of Engineering and Information Technology, University of Technology, Sydney, New South Wales 2007, Australia

Received 7 August 2009; published 20 November 2009

We provide a feasible necessary and sufficient condition for when an unknown quantum operation (quantum device) secretly selected from a set of known quantum operations can be identified perfectly within a finite number of queries, and thus complete the characterization of the perfect distinguishability of quantum operations. We further design an optimal protocol which can achieve the perfect discrimination between two quantum operations by a minimal number of queries. Interestingly, we find that an optimal perfect discrimination between two isometries is always achievable without auxiliary systems or entanglement.

© 2009 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.103.210501
DOI:
10.1103/PhysRevLett.103.210501
PACS:
03.67.Ac, 03.65.Ta, 03.67.Hk

*Runyao.Duan@uts.edu.au

 
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