Three-dimensional matter-wave vortices in optical lattices
  We predict the existence of spatially localized nontrivial vortex states of a Bose-Einstein condensate with repulsive atomic interaction confined by a three-dimensional optical lattice. Such vortex-like structures include planar vortices, their co- and counter-rotating bound states, and distinctly three-dimensional non-planar vortex states. We demonstrate numerically that many of these vortex structures are remarkably robust, and therefore can be generated and observed in experiment. 
Tristram J. Alexander, Elena A. Ostrovskaya, Andrey A. Sukhorukov and   Yuri S. Kivshar