Non-Dispersive, Accelerated Matter-Waves

It is shown that under certain dynamical conditions a material wave packet displays coherent, non-dispersive accelerated evolution in gravitational field over a modulated atomic mirror. The phenomenon takes place as a consequence of simultaneous presence of the dynamical localization and the coherent Fermi acceleration for the same modulation amplitude. It is purely a quantum mechanical effect as the windows of modulation strengths supporting dynamical localization and Fermi acceleration overlap for larger effective Plank constant. Present day experimental techniques make it feasible to realize the system in laboratory.