Directed Motion for Delta-Kicked Atoms with Broken Symmetries: Comparison between Theory and Experiment

Abstract

We report an experimental investigation of momentum diffusion in the $\ensuremath{\delta}$-function kicked rotor where time symmetry is broken by a two-period kicking cycle and spatial symmetry by an alternating linear potential. We exploit this, and a technique involving a moving optical potential, to create an asymmetry in the momentum diffusion that is due to the classical chaotic diffusion. This represents a realization of a type of Hamiltonian quantum ratchet.