Manifestation of Hamiltonian chaos in an open quantum system with   ballistic atoms in an optical lattice
  Manifestation of dynamical instability and Hamiltonian chaos in the fundamental near-resonant matter-radiation interaction has been found analitically and in a Monte Carlo simulation in the behavior of atoms moving in a rigid optical lattice. Character of diffusion of spontaneously emitting atoms changes abruptly in the range of the values of parameters and initial conditions where their Hamiltonian dynamics is shown to be chaotic 
V.Yu. Argonov and S.V. Prants