  The report deals with classical and quantum descriptions of particles that
interact with smooth random potentials, for example ultracold atoms in the
dipole potential of an optical speckle pattern. In addition, a discussion of
the link between Radiative Transfer theory and the underlying coherence theory
of wave optics is presented. The Radiative Transfer Equation is shown to emerge
as a limiting case of the Bethe-Salpeter Equation, and some next-order
corrections are discussed.
