Gray solitons, vortices, and superfluidity in Bose condensates

Summary form only given.The self-interaction of the mean field in Bose condensates introduces a nonlinearity that allows stable structures, including gray solitons (in one spatial dimension) and vortices (in two and three dimensions), to exist in the mean field wave function. As well as having their own dynamic properties, these fundamental structures have a role in determining the dynamics of the bulk quantum fluid. Using the time-dependent Gross-Pitaevskii equation to model condensate evolution, we have examined a range of different scenarios where these structures can occur, and have investigated their mechanism of formation, their stability properties, and their behavior in the bulk motion of the condensate.