Transport of a single ion in an optical lattice: spatial diffusion and energy

This paper presents a numerical study of the dynamics of a single ion subjected to a polarization gradient field, a weak confining electric potential and a periodic driving force. Comparison with laboratory experiments requires that an amplitude be chosen for the periodic force; a single value gives satisfactory agreement for both the spatial diffusion coefficient and the potential energy in the confining potential. The solution of the Fokker–Planck equation for the system in the diffusion limit allows one to explain the apparent rise of the spatial diffusion coefficient when the periodic force amplitude is increased.