OBSERVATION OF QUANTUM ACCELERATOR MODES

We have realized a quantum accelerator mode using a system consisting of ultracold cesium falling through a pulsed standing wave of off resonant light. We present a picture of this system b on diffraction and show that the effect arises from the application of blazed matter wave diffrac gratings. The implications of our results for quantum chaos and the prospect of constructing a angular separation matter wave beam splitter are discussed.