title: Direct imaging of topological edge states in cold-atom systems.
abstract: Detecting topological order in cold-atom experiments is an ongoing challenge, the resolution of which offers novel perspectives on topological matter. In material systems, unambiguous signatures of topological order exist for topological insulators and quantum Hall devices. In quantum Hall systems, the quantized conductivity and the associated robust propagating edge modes--guaranteed by the existence of nontrivial topological invariants--have been observed through transport and spectroscopy measurements. Here, we show that optical-lattice-based experiments can be tailored to directly visualize the propagation of topological edge modes. Our method is rooted in the unique capability for initially shaping the atomic gas and imaging its time evolution after suddenly removing the shaping potentials. Our scheme, applicable to an assortment of atomic topological phases, provides a method for imaging the dynamics of topological edge modes, directly revealing their angular velocity and spin structure.
authors.affiliation: Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles, B-1050 Brussels, Belgium. ngoldman@ulb.ac.be
authors.forename: Nathan
authors.initials: N
authors.lastname: Goldman
authors.forename: Jean
authors.initials: J
authors.lastname: Dalibard
authors.forename: Alexandre
authors.initials: A
authors.lastname: Dauphin
authors.forename: Fabrice
authors.initials: F
authors.lastname: Gerbier
authors.forename: Maciej
authors.initials: M
authors.lastname: Lewenstein
authors.forename: Peter
authors.initials: P
authors.lastname: Zoller
authors.forename: Ian B
authors.initials: IB
authors.lastname: Spielman
mesh_terms: D003080:Cold Temperature; D005740:Gases / Q000737:chemistry*; D008956:Models, Chemical; D044367:Phase Transition; D010825:Physics; D011789:Quantum Theory
chemical_list: D005740:Gases