title: Phase control of directed diffusion in a symmetric optical lattice.
abstract: We demonstrate the phenomenon of directed diffusion in a symmetric periodic potential. This has been realized with cold atoms in a one-dimensional dissipative optical lattice. The stochastic process of optical pumping leads to a diffusive dynamics of the atoms through the periodic structure, while a zero-mean force which breaks the temporal symmetry of the system is applied by phase modulating one of the lattice beams. The atoms are set into directed motion as a result of the breaking of the temporal symmetry of the system.
authors.affiliation: Laboratoire Kastler Brossel, Département de Physique de l'Ecole Normale Supérieure, 24, rue Lhomond, 75231, Paris Cedex 05, France.
authors.forename: M
authors.initials: M
authors.lastname: Schiavoni
authors.forename: L
authors.initials: L
authors.lastname: Sanchez-Palencia
authors.forename: F
authors.initials: F
authors.lastname: Renzoni
authors.forename: G
authors.initials: G
authors.lastname: Grynberg