Observation of Noise and Dissipation Effects on Dynamical Localization

We observe the effects of noise and dissipation on dynamical localization. Our system consists of cold cesium atoms in a pulsed standing wave of light, and is an experimental realization of the δ-kicked rotor. We compare the effects of amplitude noise with those of spontaneous scattering. The experimental signature in both cases is an increased growth in energy, with qualitatively similar momentum distributions.