Quantum correlations and secret bits.

It is shown that (i) all entangled states can be mapped by single-copy measurements into probability distributions containing secret correlations, and (ii) if a probability distribution obtained from a quantum state contains secret correlations, then this state has to be entangled. These results prove the existence of a two-way connection between secret and quantum correlations in the process of preparation. They also imply that either it is possible to map any bound entangled state into a distillable probability distribution or bipartite bound information exists.

[1]  J. Ignacio Cirac,et al.  Multipartite Bound Information exists and can be activated , 2004, Physical review letters.

[2]  M. Lewenstein,et al.  Entanglement as a precondition for secure quantum key distribution. , 2003, Physical review letters.

[3]  Barbara M. Terhal.  Is entanglement monogamous? , 2004, IBM J. Res. Dev..

[4]  I Devetak,et al.  Relating quantum privacy and quantum coherence: an operational approach. , 2004, Physical review letters.

[5]  O. Gühne.  Characterizing entanglement via uncertainty relations. , 2003, Physical review letters.

[6]  H. Hofmann.  Bound entangled states violate a nonsymmetric local uncertainty relation , 2003, quant-ph/0305003.

[7]  N. Gisin,et al.  Equivalence between two-qubit entanglement and secure key distribution. , 2003, Physical review letters.

[8]  S. Popescu,et al.  Classical analog of entanglement , 2001, quant-ph/0107082.

[9]  M. Horodecki,et al.  The asymptotic entanglement cost of preparing a quantum state , 2000, quant-ph/0008134.

[10]  J. Cirac,et al.  Optimization of entanglement witnesses , 2000, quant-ph/0005014.

[11]  Shor,et al.  Simple proof of security of the BB84 quantum key distribution protocol , 2000, Physical review letters.

[12]  Ueli Maurer,et al.  Unconditionally Secure Key Agreement and the Intrinsic Conditional Information , 1999, IEEE Trans. Inf. Theory.

[13]  M. Horodecki,et al.  General teleportation channel, singlet fraction and quasi-distillation , 1998, quant-ph/9807091.

[14]  Charles H. Bennett,et al.  Mixed-state entanglement and quantum error correction. , 1996, Physical review. A, Atomic, molecular, and optical physics.

[15]  R. Jozsa,et al.  A Complete Classification of Quantum Ensembles Having a Given Density Matrix , 1993 .

[16]  Charles H. Bennett,et al.  Quantum cryptography without Bell's theorem. , 1992, Physical review letters.

[17]  Ekert,et al.  Quantum cryptography based on Bell's theorem. , 1991, Physical review letters.

[18]  Werner,et al.  Quantum states with Einstein-Podolsky-Rosen correlations admitting a hidden-variable model. , 1989, Physical review. A, General physics.

[19]  J. Bell.  On the Einstein-Podolsky-Rosen paradox , 1964 .