title: Ratchet effect for cold atoms in an optical lattice.
abstract: The possibility of realizing a directed current for a quantum particle in a flashing asymmetric potential is investigated. It is found that quantum resonances, where the value of the effective Planck constant is equal to an integer or half-integer multiple of pi, give rise to a directed current. The effect should be readily observable in experiments.
authors.affiliation: Department of Physics, Royal Institute of Technology, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: Emil
authors.initials: E
authors.lastname: Lundh
authors.forename: Mats
authors.initials: M
authors.lastname: Wallin