title: Motional dressed states in a bose-einstein condensate: superfluidity at supersonic speed
abstract: We present an exact analytic solution of a nonlinear Schrodinger field interacting with a moving potential (obstacle) at supersonic speed. We discover conditions under which the field can form a stable shape-invariant structure localized around the obstacle-a dressing effect that protects the field against excitations by the obstacle. Such an effect demonstrates the existence of frictionless motion beyond the conventionally defined critical velocity.
authors.affiliation: Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.initials: CK
authors.lastname: Law
authors.initials: CM
authors.lastname: Chan
authors.initials: PT
authors.lastname: Leung
authors.initials: M
authors.lastname: Chu