Effect of interactions on the localization of a Bose-Einstein condensate   in a quasi-periodic lattice
  The transport properties of a Bose-Einstein condensate in a 1D incommensurate bichromatic lattice are investigated both theoretically and experimentally. We observe a blockage of the center of mass motion with low atom number, and a return of motion when the atom number is increased. Solutions of the Gross-Pitaevskii equation show how the localization due to the quasi-disorder introduced by the incommensurate bichromatic lattice is affected by the interactions. 
J. E. Lye, L. Fallani, C. Fort, V. Guarrera, M. Modugno, D. S.   Wiersma, and M. Inguscio