Damping of Bogoliubov excitations in optical lattices

Journal Article · Sun Aug 01 04:00:00 EDT 2004 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.70.023611· OSTI ID:20645938

Tsuchiya, Shunji ^[1]; Griffin, Allan ^[1]

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1. Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7 (Canada)

Extending recent work to finite temperatures, we calculate the Landau damping of a Bogoliubov excitation in an optical lattice, due to the coupling to a thermal cloud of such excitations. For simplicity, we consider a one-dimensional Bose-Hubbard model and restrict ourselves to the first energy band. For energy conservation to be satisfied, the excitations in the collision processes must exhibit ''anomalous dispersion,'' analogous to phonons in superfluid {sup 4}He. This leads to the disappearance of all damping processes when Un{sup c0}{>=}6J, where U is the on-site interaction, J is the hopping matrix element, and n{sup c0}(T) is the number of condensate atoms at a lattice site. This phenomenon also occurs in two-dimensional and three-dimensional optical lattices. The disappearance of Beliaev damping above a threshold wave vector is noted.

• OSTI ID: 20645938
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 70; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
ATOMS
BOSE-EINSTEIN CONDENSATION
COOLING
COUPLING
ENERGY CONSERVATION
EXCITATION
HELIUM 4
HUBBARD MODEL
LANDAU DAMPING
MATRIX ELEMENTS
ONE-DIMENSIONAL CALCULATIONS
PHONONS
SUPERFLUIDITY
THREE-DIMENSIONAL CALCULATIONS
TWO-DIMENSIONAL CALCULATIONS
VECTORS