Abstract
We study bosonic atoms in small optical lattices by exact diagonalization and observe a striking similarity to the superfluid to Mott insulator transition in macroscopic systems. The momentum distribution, the formation of an energy gap, and the pair correlation function show only a weak size dependence. For noncommensurate filling we reveal in deep lattices a mixture of localized and delocalized particles, which is sensitive to lattice imperfections. Breaking the lattice symmetry causes a Bose-glass-like behavior. We discuss the nature of excited states and orbital effects by using an exact diagonalization technique that includes higher bands.
Original language | English |
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Journal | Physical Review A |
Volume | 77 |
Issue number | 2 |
Early online date | 1 Feb 2008 |
DOIs | |
Publication status | Published - 1 Feb 2008 |