[quantum-info] IQC colloquium Nov 5

[Debbie Leung]

Dr. Graeme Smith, IBM TJ Watson Research Center

RAC1 2009 (old)

Nov 05, 2012 (Monday)
02:30 PM to 03:25 PM (new)


Abstract:

An accurate model of a physical communication device must include
quantum effects, but typically this makes the theory intractable. As a
result communication capacities are not known, even for transmission
between two users connected by an
electromagnetic waveguide subject to gaussian noise. We present an
exactly solvable model of noisy communications with a fully quantum
electromagnetic field. This allows us to find explicit expressions for
all point-to-point capacities. We also develop a theory of quantum
networks by solving some rudimentary networks such as broadcasting and
multiple access. When possible, we compare the predictions of our new
model with those of the orthodox quantum gaussian model and in all
cases we find capacities in agreement to within a few bits. Thus, in
the limit of high signal to noise ratios our simple model captures the
relevant physics of gaussian models while remaining amenable to
detailed analysis.

Joint work with John Smolin