Fragmentation of Bose-Einstein condensates in multi-well three-dimensional traps

The present Letter analyzes the ground-state of weakly-interacting cold bosonic atoms in three-dimensional (3D) multi-well traps. A physical repulsive pairwise interaction is considered. As the interparticle interaction is increased, fragmentation of condensates is established and discussed. Analogously, superfluid to Mott-insulator transitions are described by a continuum real-space approach. In a related context, we also discuss the fermionization of cold bosonic systems in and beyond 1D. Illustrative numerical examples for fragmentation in 3D and 2D and fermionization in 1D traps are provided.