Quantum signatures of anomalous diffusion

Summary form only given. It is well established that classical chaotic motion is suppressed by quantum mechanics. A paradigm theoretical system for the study of this suppression is the kicked rotor, where the suppression manifests itself as dynamical localization. This effect is the saturation of momentum growth after the quantum break time, with a resulting exponentially localized distribution. Classical analyses of this system have also identified regimes of anomalous diffusion, characterized by Levy flights in phase space. This behavior is considerably more complex than normal diffusion and has attracted much interest in recent years. In the quantum case, recent theoretical work suggests that the transport properties of the system can again be strongly modified when anomalous diffusion occurs in the classical system. We report an experimental study of quantum signatures of anomalous diffusion in an atom optics realization of the quantum kicked rotor. Our system consists of laser-cooled cesium atoms in a pulsed standing wave of light.