Ballistic and localized transport for the atom optics kicked rotor in   the limit of vanishing kicking period
  We present mean energy measurements for the atom optics kicked rotor as the kicking period tends to zero. A narrow resonance is observed marked by quadratic energy growth, in parallel with a complete freezing of the energy absorption away from the resonance peak. Both phenomena are explained by classical means, taking proper account of the atoms' initial momentum distribution. 
Mark Sadgrove, Sandro Wimberger, Scott Parkins, Rainer Leonhardt