Anomalous dynamics of atoms in a 1D dissipative optical lattices
In this talk I will present an experimental study of the anomalous dynamics of ultra-cold Rb atoms propagating in a 1D, dissipative, Sisyphus-type optical lattice. We find that the width of the cloud exhibits a power-law time dependence with an exponent that depends on the lattice depth. Moreover, the distribution exhibits fractional self-similarity with the same characteristic exponent. The self-similar shape of the distribution is found to be well fitted by a Lévy distribution. I will further present a measurement of the phase-space density distribution (PSDD) of the cloud of atoms. The PSDD is imaged using a direct tomographic method comprised of velocity selection and spatial imaging. We show that the position-velocity correlation function, obtained from the PSDD, decays asymptotically as a function of time with a power-law that we relate to a simple scaling theory involving the power-law asymptotic dynamics of the position and velocity. The generality of this scaling theory is confirmed using Monte-Carlo simulations of two distinct models of anomalous diffusion dynamics.