QUANTUM REFLECTION FROM AN ATOMIC MIRROR

We calculate the reflection probability for ultracold atoms incident o n an evanescent-wave atomic mirror, and analyze the optimum conditions to observe quantum reflection. We find that averaging over the Gaussi an profile of the laser beam dramatically reduces the quantum signatur e, and consider the effects of an appropriate aperture that limits the variation of beam intensity. We show that quantum reflection is parti cularly sensitive to details of the atom-surface potential. and could be used to resolve retardation effects. [S1050-2947(97)50611-1].