Physical Review A
Atomic transport on one-dimensional optical lattices
W. Greenwood, Paul H. Pax, Pierre Meystre
Abstract
We carry out quantum and semiclassical numerical simulations of the dynamics, particularly diffusion, of atoms in an optical lattice. We consider specifically the situation of a $J=1/2\ensuremath{\leftrightarrow}J=3/2$ atomic transition, whose experimental counterpart can be realized in ${\mathrm{Mg}}^{+}$ experiments. The semiclassical results, which cover a larger range of parameters than would be practical for fully quantum calculations, confirm and extend the work of Marksteiner et al. [Phys. Rev. A 53, 3409 (1996)], characterize the transition from normal to anomalous diffusion and the atomic trajectories which give rise to it, and provide a physical explanation for the difference between these two regimes. The full quantum calculations reveal uniquely quantum features of individual atomic trajectories, and in addition, predict significantly lower diffusion, by a factor of 1.2 to 2, than their semiclassical counterparts.