Locking classical correlations in quantum States.
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.
DiVincenzo
David P
DP
IBM Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598, USA.
Horodecki
Michał
M
Leung
Debbie W
DW
Smolin
John A
JA
Terhal
Barbara M
BM