"Toricboson model: Toward a topological quantum memory at finite temperature"Alioscia Hamma , Perimeter Institute [Host: Israel Klich]
ABSTRACT:
We discuss the existence of stable topological quantum memory at finite
temperature. At stake here is the fundamental question of whether it is, in
principle, possible to store quantum information for macroscopic times
without the intervention from the external world, that is, without error
correction. We study the toric code in two dimensions with an additional
bosonic field that couples to the defects, in the presence of a generic
environment at finite temperature: the toricboson model. Although the
coupling constants for the bare model are not finite in the thermodynamic
limit, the model has a finite spectrum. We show that in the topological
phase, there is a finite temperature below which open strings are confined
and therefore the lifetime of the memory can be made arbitrarily
(polynomially) long in system size. The interaction with the bosonic field
yields a longrange attractive force between the end points of open strings
but leaves closed strings and topological order intact.

Condensed Matter Seminar Thursday, September 17, 2009 4:00 PM Physics Building, Room 204 Note special time. Note special room. 
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