Influence of a dark soliton on the reflection of a Bose–Einstein condensate by a square barrier

We study the quantum reflection of a two-dimensional disk-shaped Bose–Einstein condensate with dark soliton excitation by a square potential barrier. For the given geometry, the dark soliton initially located at the centre of the condensate cloud survives long enough to investigate the reflection process. We show the time evolution of the reflection probability with respect to various widths of the barrier. The asymptotic value of the reflection probability is decreased by the existence of a dark soliton, and is highly sensitive to the initial orientation of the dark soliton, which also affects the excitation properties during the process of condensate and barrier interaction. (paper)