We exploit the variation of the atomic interaction in order to move
ultra-cold atoms across an AC-driven periodic lattice. By breaking relevant
symmetries, a gathering of atoms is achieved. Accurate control of the gathered
atoms positions can be demonstrated via the control of the atomic localization
process. The localization process is analyzed with the help of the nonlinear
Floquet states where the Landau-Zener tunneling between states is observed and
controlled. Transport effects in the presence of disorder are discussed.Comment: 14 pages, 5 Figures, PACS numbers: 03.75.Lm, 05.60.-k, 63.20.P
