Relaxation to negative temperature breathers in Bose-Einstein Condensates in optical lattices

Abstract

Localization of Bose-Einstein Condensates (BEC) in optical lattices has been predicted and observed by suitable preparation of the initial atomic packet [1]. In the deep potential limit, the dynamics of the BEC is well described by the Discrete Nonlinear Schrodinger Equation (DNLSE) where the transport mechanism of the atomic density across the lattice is due to tunneling effects. Highly localized states of the atomic density corresponding to discrete breathers can be achieved by progressively removing atoms at the boundaries of the optical lattice [1,2]. Both static breathers with fixed spatial position and travelling breathers can be obtained with this relaxation technique [1,2].