title: Bogoliubov-Cerenkov radiation in a Bose-Einstein condensate flowing against an obstacle.
abstract: We study the density modulation that appears in a Bose-Einstein condensate flowing with supersonic velocity against an obstacle. The experimental density profiles observed at JILA are reproduced by a numerical integration of the Gross-Pitaevskii equation and then interpreted in terms of Cerenkov emission of Bogoliubov excitations by the defect. The phonon and the single-particle regions of the Bogoliubov spectrum are, respectively, responsible for a conical wave front and a fan-shaped series of precursors.
authors.affiliation: CNR-BEC-INFM, Trento, I-38050 Povo, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Carusotto
authors.forename: S X
authors.initials: SX
authors.lastname: Hu
authors.forename: L A
authors.initials: LA
authors.lastname: Collins
authors.forename: A
authors.initials: A
authors.lastname: Smerzi