title: Observation of vortex pinning in Bose-Einstein condensates.
abstract: We report the observation of vortex pinning in rotating gaseous Bose-Einstein condensates. Vortices are pinned to columnar pinning sites created by a corotating optical lattice superimposed on the rotating Bose-Einstein condensates. We study the effects of two types of optical lattice: triangular and square. In both geometries we see an orientation locking between the vortex and the optical lattices. At sufficient intensity the square optical lattice induces a structural crossover in the vortex lattice.
authors.affiliation: JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA.
authors.forename: S
authors.initials: S
authors.lastname: Tung
authors.forename: V
authors.initials: V
authors.lastname: Schweikhard
authors.forename: E A
authors.initials: EA
authors.lastname: Cornell