Atom optics in nonlinear potentials

Summary form only given. The study of quantum systems that are chaotic in their classical limit has been the subject of intense research in recent years. Atom optics is an ideal experimental testing ground for this field given the combination of well-defined initial conditions, controlled nonlinear potentials, and absence of dissipative processes. To study nonlinear effects in the simplest setting, we measure momentum transferred from a single pulse of a standing wave of light to a sample of ultracold Na atoms, and observe a sharp increase in the momentum transfer when the pulse duration exceeds a critical value.