Seminar @ DF - Fri Dec 5th 3.00 pm - M. Piani

[Rosita Glavina - Dip. Fisica, UniTS]

We are pleased to announce the seminar @ DF UniTs:
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Marco Piani

SUPA and Department of Physics, University of Strathclyde, Glasgow 
(U.K.)

"Usefulness of entanglement and steering in the discrimination of 
physical processes"

Friday December 5th 2014 - 3:00 pm
Room 204, LB - ICTP
Dip. di Fisica - Strada Costiera, 11- Trieste

ABSTRACT
Not all entangled states are created equal: they are all special, but
some are more special than others. In particular, this is true in an
operational characterization of quantum correlations based on their
usefulness in the discrimination of physical processes. We will discuss
how every entangled state of a probe-ancilla composite system is useful
as a resource for the problem of minimum-error channel discrimination.
We will then focus on the subset of entangled states that exhibit
steering. The latter is the entanglement-based quantum effect that
embodies the "spooky action at a distance" disliked by Einstein and
scrutinized by Einstein, Podolsky, and Rosen. We prove that, for any
fixed steerable state, there are instances of a generalization of the
channel discrimination problem, which we dub quantum subchannel
discrimination, where such a state allows a correct discrimination with
strictly higher probability than in absence of entanglement, even when
measurements are restricted to local measurements aided by one-way
communication. On the other hand, unsteerable states are useless under
such a restriction, even when entangled. We also prove that the above
steering advantage can be exactly quantified in terms of the steering
robustness, which is a natural measure of the steerability exhibited by
the state.

Joint work with J. Watrous, arXiv:1406.0530

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The calendar of seminars taking place at the Physics Department is 
available at http://df.units.it/