2003/11/13 by Shunji Tsuchiya, S. Tsuchiya, Allan Griffin +1
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Quantum, superfluid, helium dynamics #Strong Light-Matter Interactions #cond-mat.soft #cond-mat.stat-mech
paper · pdf · doi:10.1103/physreva.70.023611
4pages, 5figures, submitted to Phys. Rev. Lett
arxiv created 2003/11/13 · openalex publication_date 2004/08/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 4He. This leads to the disappearance of all damping processes when Unc0\ensuremath\geqslant6J, where U is the on-site interaction, J is the hopping matrix element, and nc0(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.