Hi I have two questions regarding atom-light interaction. 1) Usually when we look at e.g. slowing atoms by a laser beam, we model the atom as a classical particle, i.e. we deal with a force F and not an operator. I was wondering why we are allowed to do that. Is it because the atom is small compared to the distancve over which the intensity of the beam changes? 2) Is it correct to say that as long as we have *many* photons, then the particular light beam we look at can be described classically? I know I haven't quantified what "many" is, but I hope the idea is clear. Best regards, Niles.