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CATEGORIES:CQIF Seminar
SUMMARY:Entropy of a correlation matrix and (in)fidelity b
etween several quantum states - Karol Zyczkowski (
Jagiellonian University Cracow\, Poland)
DTSTART;TZID=Europe/London:20110127T141500
DTEND;TZID=Europe/London:20110127T151500
UID:TALK28506AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/28506
DESCRIPTION:Making use of the strong subadditivity of entropy
we prove that the Holevo quantity for an ensemble
of k quantum states is not larger than the entropy
of a certain correlation matrix. In the case of k
=2 states\nthe minimum over the set of admissible
correlation matrices is found to be given by a fun
ction of the fidelity between both states. This im
plies an upper bound for the coherent information
and the quantum\nJensen--Shannon divergence. Restr
icting our attention to classical information we b
ound the transmission distance between any two pr
obability distributions by the entropic distance\,
which is a concave function of the Hellinger dist
ance.\n\nFor larger number of k states in an ensem
ble we find\nexplicit bounds for the exchange entr
opy\, which could be used to characterize disting
uishability between them.
LOCATION:MR13\, Centre for Mathematical Sciences
CONTACT:Ashley Montanaro
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