Roton confinement in trapped dipolar Bose-Einstein condensates
M. Jona-Lasinio, Kazimierz Łakomy, Luis Santos
Roton excitations constitute a key feature of dipolar gases, connecting these gases with superfluid helium. We show that the density dependence of the roton minimum results in a spatial roton confinement, particularly relevant in pancake dipolar condensates with large aspect ratios. We show that roton confinement plays a crucial role in the dynamics after roton instability, and that arresting the instability may create a trapped roton gas revealed by confined density modulations. We discuss the local susceptibility against density perturbations, which we illustrate for the case of vortices. Roton confinement is expected to play a key role in experiments.
arXiv:1301.4907•Physical Review A•Jul 12, 2013•43 citations