Critical velocity for superfluidity of a generalized Gross-Pitaevskii flow past a localized obstacle in one dimension

Pierre-Élie Larré

A one-dimensional quantum fluid flows past a localized obstacle. Below a certain speed, its motion is superfluid: overall steady and asymptotically subsonic and devoid of hydrodynamic disturbances. How does this critical velocity for superfluidity depend on the parameters of the obstacle? We analytically and numerically answer this question for localized obstacles of arbitrary height (or depth) and width, for any local interaction potential, and for particle losses in the adiabatic-evolution approximation. Our work paves the way for further investigations in higher dimensions and is relevant for experiments on superfluidity in atom and photon quantum fluids.