title: Dynamical vortex phases in a Bose-Einstein condensate driven by a rotating optical lattice.
abstract: We present simulation results of the vortex dynamics in a trapped Bose-Einstein condensate in the presence of a rotating optical lattice. Changing the potential amplitude and the relative rotation frequency between the condensate and the optical lattice, we find a rich variety of dynamical phases of vortices. The onset of these different phases is described by the force balance of a driving force, a pinning force, and vortex-vortex interactions. In particular, when the optical lattice rotates faster than the condensate, an incommensurate effect leads to a vortex-liquid phase supported by the competition between the driving force and the dissipation.
authors.affiliation: Department of General Education, Ishikawa National College of Technology, Tsubata, Ishikawa 929-0392, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kasamatsu
authors.forename: Makoto
authors.initials: M
authors.lastname: Tsubota