Phase diagram of bosonic atoms in two-color superlattices

Journal Article · Fri Aug 01 00:00:00 EDT 2003 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.68.023604· OSTI ID:20640088

Roth, Robert; Burnett, Keith ^[1]

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1. Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt, (Germany)

We investigate the zero-temperature phase diagram of a gas of bosonic atoms in one- and two-color standing-wave lattices in the framework of the Bose-Hubbard model. We first introduce some relevant physical quantities; superfluid fraction, condensate fraction, quasimomentum distribution, and matter-wave interference pattern. We then discuss the relationships between them on the formal level and show that the superfluid fraction, which is the relevant order parameter for the superfluid to Mott-insulator transition, cannot be probed directly via the matter-wave interference patterns. The formal considerations are supported by exact numerical solutions of the Bose-Hubbard model for uniform one-dimensional systems. We then map out the phase diagram of bosons in nonuniform lattices. The emphasis is on optical two-color superlattices which exhibit a sinusoidal modulation of the well depth and can be easily realized experimentally. From the study of the superfluid fraction, the energy gap, and other quantities, we identify additional zero-temperature phases, including a localized and a quasi-Bose-glass phase, and discuss prospects for their experimental observation.

• OSTI ID: 20640088
• Journal Information: Physical Review. A, Vol. 68, Issue 2; Other Information: DOI: 10.1103/PhysRevA.68.023604; (c) 2003 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
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATOMS
BOSE-EINSTEIN CONDENSATION
BOSONS
COLOR
DISTRIBUTION
ENERGY GAP
HUBBARD MODEL
INTERFERENCE
LATTICE FIELD THEORY
MODULATION
NUMERICAL SOLUTION
ONE-DIMENSIONAL CALCULATIONS
ORDER PARAMETERS
PHASE DIAGRAMS
STANDING WAVES
SUPERFLUIDITY
SUPERLATTICES