title: Quantum gray solitons in confining potentials.
abstract: We define and study holelike excitations (the Lieb II mode) in a weakly interacting Bose liquid subject to external confinement. These excitations are obtained by semiclassical quantization of gray solitons propagating on top of a Thomas-Fermi background. Radiation of phonons by an accelerated gray soliton leads to a finite lifetime of these excitations. It is shown that, for a large number of trapped atoms, most of the Lieb II levels can be experimentally resolved.
authors.affiliation: School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
authors.forename: Dominic C
authors.initials: DC
authors.lastname: Wadkin-Snaith
authors.forename: Dimitri M
authors.initials: DM
authors.lastname: Gangardt