title: Polariton superfluids reveal quantum hydrodynamic solitons.
abstract: A quantum fluid passing an obstacle behaves differently from a classical one. When the flow is slow enough, the quantum gas enters a superfluid regime, and neither whirlpools nor waves form around the obstacle. For higher flow velocities, it has been predicted that the perturbation induced by the defect gives rise to the turbulent emission of quantized vortices and to the nucleation of solitons. Using an interacting Bose gas of exciton-polaritons in a semiconductor microcavity, we report the transition from superfluidity to the hydrodynamic formation of oblique dark solitons and vortex streets in the wake of a potential barrier. The direct observation of these topological excitations provides key information on the mechanisms of superflow and shows the potential of polariton condensates for quantum turbulence studies.
authors.affiliation: Laboratoire Kastler Brossel, Université Pierre et Marie Curie-Paris 6, École Normale Supérieure et CNRS, UPMC Case 74, 4 place Jussieu, 75005 Paris, France. alberto.amo@lpn.cnrs.fr
authors.forename: A
authors.initials: A
authors.lastname: Amo
authors.forename: S
authors.initials: S
authors.lastname: Pigeon
authors.forename: D
authors.initials: D
authors.lastname: Sanvitto
authors.forename: V G
authors.initials: VG
authors.lastname: Sala
authors.forename: R
authors.initials: R
authors.lastname: Hivet
authors.forename: I
authors.initials: I
authors.lastname: Carusotto
authors.forename: F
authors.initials: F
authors.lastname: Pisanello
authors.forename: G
authors.initials: G
authors.lastname: Leménager
authors.forename: R
authors.initials: R
authors.lastname: Houdré
authors.forename: E
authors.initials: E
authors.lastname: Giacobino
authors.forename: C
authors.initials: C
authors.lastname: Ciuti
authors.forename: A
authors.initials: A
authors.lastname: Bramati