Superfluidity and interference pattern of ultracold bosons in optical lattices

Journal Article · Sat Mar 01 04:00:00 EST 2003 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.67.031602· OSTI ID:20633801

Roth, R; Burnett, K ^[1]

---

1. Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

We present a study of the superfluid properties of atomic Bose gases in optical lattice potentials using the Bose-Hubbard model. To do this, we use a microscopic definition of the superfluid fraction based on the response of the system to a phase variation imposed by means of twisted boundary conditions. We compare the superfluid fraction to other physical quantities, i.e., the interference pattern after ballistic expansion, the quasimomentum distribution, and number fluctuations. We have performed exact numerical calculations of all these quantities for small one-dimensional systems. We show that the superfluid fraction alone exhibits a clear signature of the Mott-insulator transition. Observables like the fringe visibility, which probe only ground-state properties, do not provide direct information on superfluidity and the Mott-insulator transition.

• OSTI ID: 20633801
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 3 Vol. 67; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
BOSE-EINSTEIN GAS
BOSONS
BOUNDARY CONDITIONS
COMPARATIVE EVALUATIONS
EXPANSION
FLUCTUATIONS
GROUND STATES
HUBBARD MODEL
INTERFERENCE
LATTICE FIELD THEORY
METALS
ONE-DIMENSIONAL CALCULATIONS
PHASE TRANSFORMATIONS
PROBES
SUPERFLUIDITY