Article,
Phases of a Two-Dimensional Bose Gas in an Optical Lattice
Physical Review Letters, 105 (11): 110401+ (September 2010)
DOI: 10.1103/physrevlett.105.110401
Abstract
Ultracold atoms in optical lattices realize simple condensed matter models. We create an ensemble of ≈60 harmonically trapped 2D Bose-Hubbard systems from a 87Rb Bose-Einstein condensate in an optical lattice and use a magnetic resonance imaging approach to select a few 2D systems for study, thereby eliminating ensemble averaging. Our identification of the transition from superfluid to Mott insulator, as a function of both atom density and lattice depth, is in excellent agreement with a universal state diagram M. Rigol et al., Phys. Rev. A 79 053605 (2009) suitable for our trapped system. In agreement with theory, our data suggest a failure of the local density approximation in the transition region.
