Locking Classical Correlations in Quantum States

David P. DiVincenzo, Michał Horodecki, Debbie W. Leung, John A. Smolin, Barbara M. Terhal

Research output: Contribution to journalArticleScientificpeer-review

184 Citations (Scopus)


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 [Formula presented]-qubit states for which a one-bit message doubles the optimal classical mutual information between measurement results on the subsystems, from [Formula presented] bits to [Formula presented] 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.
Original languageEnglish
Article number067902
Pages (from-to)067902-1 - 067902-4
Number of pages4
JournalPhysical Review Letters
Issue number6
Publication statusPublished - 2004
Externally publishedYes


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