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CATEGORIES:CQIF Seminar
SUMMARY:Tradeoff relations between accessible information\
, informational power\, and purity - Michele Dall'
Arno
DTSTART;TZID=Europe/London:20200116T141500
DTEND;TZID=Europe/London:20200116T151500
UID:TALK137671AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/137671
DESCRIPTION:The accessible information and the informational p
ower quantify the maximum amount of information th
at can be extracted from a quantum ensemble and by
a quantum measurement\, respectively. Here\, we i
nvestigate the tradeoff between the accessible inf
ormation (informational power\, respectively) and
the purity of the states of the ensemble (the elem
ents of the measurement\, respectively). Under any
given lower bound on the purity\, i) we compute t
he minimum informational power and show that it is
attained by the depolarized uniformly-distributed
measurement\; ii) we give a lower bound on the ac
cessible information. Under any given upper bound
on the purity\, i) we compute the maximum accessib
le information and show that it is attained by an
ensemble of pairwise commuting states with at most
two distinct non-null eigenvalues\; ii) we give a
lower bound on the maximum informational power. T
he present results provide\, as a corollary\, nove
l sufficient conditions for the tightness of the J
ozsa-Robb-Wootters lower bound to the accessible i
nformation.
LOCATION:MR15\, Centre for Mathematical Sciences\, Wilberfo
rce Road\, Cambridge
CONTACT:Johannes Bausch
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