arXiv:0904.4549 · Physical Review A
Bose-Einstein condensates on tilted lattices: Coherent, chaotic, and subdiffusive dynamics
Andrey R. Kolovsky, Edgar A. Gómez, Hans Jürgen Korsch
Abstract
The dynamics of a (quasi-) one-dimensional interacting atomic Bose-Einstein condensate in a tilted optical lattice is studied in a discrete mean-field approximation, i.e., in terms of the discrete nonlinear Schr\"odinger equation. If the static field is varied, the system shows a plethora of dynamical phenomena. In the strong field limit, we demonstrate the existence of (almost) nonspreading states which remain localized on the lattice region populated initially and show coherent Bloch oscillations with fractional revivals in the momentum space (so-called quantum carpets). With decreasing field, the dynamics becomes irregular, however, still confined in configuration space. For even weaker fields, we find subdiffusive dynamics with a wave-packet width growing as ${t}^{1/4}$.