  Centre-of-mass atomic motion in an optical lattice near the resonance is
shown to be a chaotic walking due to the interplay between coherent internal
atomic dynamics and spontaneous emission. Statistical properties of chaotic
atomic motion can be controlled by the single parameter, the detuning between
the atomic transition frequency and the laser frequency. We derive a
Fokker-Planck equation in the energetic space to describe the atomic transport
near the resonance and demonstrate numerically how to manipulate the atomic
motion varying the detuning.
