Localization and delocalization of ultracold bosonic atoms in finite optical lattices

Journal Article · Fri Feb 15 00:00:00 EST 2008 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.77.023620· OSTI ID:21140541

Luehmann, Dirk-Soeren; Pfannkuche, Daniela ^[1]; Bongs, Kai ^[2]; Sengstock, Klaus ^[2]

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1. Institut fuer Theoretische Physik, Universitaet Hamburg, Jungiusstrasse 9, 20355 Hamburg (Germany)
2. Institut fuer Laser-Physik, Universitaet Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)

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.

• OSTI ID: 21140541
• Journal Information: Physical Review. A, Vol. 77, Issue 2; Other Information: DOI: 10.1103/PhysRevA.77.023620; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ATOMS
BOSONS
COOLING
CORRELATION FUNCTIONS
DEFECTS
DISTRIBUTION
ENERGY GAP
EXCITED STATES
LASER RADIATION
MIXTURES
OPTICAL MODELS
PARTICLES
SUPERFLUIDITY
SYMMETRY
SYMMETRY BREAKING
TEMPERATURE RANGE 0000-0013 K