Speaker
Thomas Gobeil
(University of Sherbrooke)
Description
We study the existence of stable topological quantum memory at finite temperature. This aids
in tackling the fundamental problematic of storing quantum information for macroscopically
significant times without the use of external intervention in the form of error correction. It
has been argued before that a gravitational attraction could confine the anyonic excitations in
a topological material, thus preventing them from altering the topological information stored
in the system. This idea has led Hamma et al. (2009) to propose a model in which the toric
code qubits are coupled to a bosonic bath materializing the gravitational force. Although
this confinement is well established for ordinary matter, it has not been observed before for
Z2-type excitations, i.e., particles whose mass is preserved only modulo 2. We study this
question using numerical simulations wich are performed on a continuous lattice in which
the thermal processes were limited to creation, annihilation, and diffusion, with the latter
being constrained by an additional energy cost. While preliminary data does not indicate
the presence of a defect density threshold in the topological phase below which open strings
are confined and the topological order remains intact, our results do not dismiss its existence
conclusively and warrant further inquiry.
Authors
Prof.
David Poulin
(University of Sherbrooke)
Thomas Gobeil
(University of Sherbrooke)
