Duplicate of Quasi 1D Bose–Einstein condensate flow past a nonlinear barrier

The problem of a quasi 1D repulsive BEC flow past wide and narrow nonlinear barriers is investigated. It is shown that in contrast to the linear barrier case, for a wide nonlinear barrier an interval of velocities 0 < v < v− always exists, where the flow is superfluid regardless of the barrier potential strength. In the case of a short range barrier stable and unstable steady solutions exist below some critical velocity. An unstable solution is shown to decay into a gray soliton moving downstream and a stable solution located at the barrier position.

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