Description
Robust edge states and non-Abelian excitations are the
trademark of topological states of matter, with promising
applications such as "topologically protected" quantum
memory and computing. While so far topological phases have
been exclusively discussed in a Hamiltonian context, we show
that such phases and the associated topological protection
and phenomena also emerge in open quantum systems with
engineered dissipation. The specific system studied here is
a quantum wire of spinless atomic fermions in an optical
lattice coupled to a bath. The key feature of the
dissipative dynamics described by a Lindblad master equation
is the existence of Majorana edge modes, representing a
non-local decoherence free subspace. The isolation of the
edge states is enforced by a dissipative gap in the p-wave
paired bulk of the wire. We describe dissipative non-Abelian
braiding operations within the Majorana subspace, and we
illustrate the insensitivity to imperfections. Topological
protection is granted by a nontrivial winding number of the
system density matrix.
-Authors:
S. Diehl, E. Rico, M.A. Baranov, P. Zoller
-Reference:
arXiv:1105.5947
