Dynamical Localization: Hydrogen Atoms in Magnetic and Microwave fields
  We show that dynamical localization for excited hydrogen atoms in magnetic and microwave fields takes place at quite low microwave frequency much lower than the Kepler frequency. The estimates of localization length are given for different parameter regimes, showing that the quantum delocalization border drops significantly as compared to the case of zero magnetic field. This opens up broad possibilities for laboratory investigations. 
Francesco Benvenuto, Giulio Casati and Dima L. Shepelyansky