Quantum chaos with cold cesium atoms

Atomic motion in a time-dependent standing wave of light provides an almost ideal experimental system for the study of quantum chaos, due to the nonli nearity of the potential combined with negligible dissipation. In our first experiments with sodium atoms we observed dynamical localization, a quantu m suppression of chaotic diffusion. To go beyond this work we have construc ted an experiment with cold cesium atoms and report our first results from this system. The larger mass and longer wavelength push out the momentum bo undary in phase space that arises from the nonzero duration of the pulses. This feature should enable the study of effects leading to delocalization.