Topology by dissipation: Transport properties

Topological phases of matter are the center of much current interest, with promising potential applications in, e.g., topologically protected transport and quantum computing. Traditionally such states are prepared by tuning the system Hamiltonian while coupling it to a generic bath at very low temperatures. However, this approach is often ineffective, especially in cold-Atom systems. It was recently shown that topological phases can emerge much more efficiently even in the absence of a Hamiltonian, by properly engineering the interaction of the system with its environment, to directly drive the system into the desired state. Here we concentrate on dissipatively induced two-dimensional Chern insulator (lattice quantum Hall) states. We employ open quantum systems tools to explore their transport properties, such as persistent currents and the conductance in the steady state, in the presence of various Hamiltonians. We find that, in contrast with equilibrium systems, the usual confinement of currents to the edge, as well as the usual relation between the Chern topological number and the Hall conductance, could be broken. We explore the intriguing edge behaviors and elucidate under which conditions the Hall conductance is quantized.