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Locking Classical Correlations in Quantum States

DiVincenzo, David P. and Horodecki, Michał and Leung, Debbie W. and Smolin, John A. and Terhal, Barbara M. (2004) Locking Classical Correlations in Quantum States. Physical Review Letters, 92 (6). Art. No. 067902. ISSN 0031-9007. doi:10.1103/PhysRevLett.92.067902.

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We show that there exist bipartite quantum states which contain a large locked classical correlation that is unlocked by a disproportionately small amount of classical communication. In particular, there are (2n + 1)-qubit states for which a one-bit message doubles the optimal classical mutual information between measurement results on the subsystems, from n/2 bits to n bits. This phenomenon is impossible classically. However, states exhibiting this behavior need not be entangled. We study the range of states exhibiting this phenomenon and bound its magnitude.

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Additional Information:© 2004 The American Physical Society (Received 13 March 2003; published 12 February 2004) We thank I. Devetak and C. Bennett for extremely helpful discussions, W. Wootters for enlightening discussion on mutually unbiased bases, and D. Gottesman for a discussion on complete locking. Part of this work was completed while M.H. was visiting at the MSRI program on Quantum Computation. M.H. is supported by EC, Contract No. IST-2001-37559 (RESQ), IST-2001-38877 (QUPRODIS), and also by EQUIP. D.P.DV., J.A.S., and B.M.T. are supported in part by the NSA and the ARDA through ARO Contract No. DAAD19-01-C-0056. D.W. L. acknowledges support from the Tolman Endowment Fund and the NSF under Grant No. EIA-0086038.
Subject Keywords:quantum entanglement; quantum communication
Issue or Number:6
Record Number:CaltechAUTHORS:DIVprl04
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4509
Deposited By: Archive Administrator
Deposited On:25 Aug 2006
Last Modified:08 Nov 2021 20:17

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