Defect modes of a Bose-Einstein condensate in an optical lattice with a localized impurity
V.A. Brazhnyi, V.V. Konotop, V.M. Pérez-García
Physical Review A, 74, 023614 (2006).
Pérez García, Victor M..
We study defect modes of a Bose-Einstein condensate in an optical lattice with a localized defect within the framework of the one-dimensional Gross-Pitaevskii equation. It is shown that for a significant range of parameters the defect modes can be accurately described by an expansion over Wannier functions, whose envelope is governed by the coupled nonlinear Schrödinger equations with a impurity. The stability of the defect modes is verified by direct numerical simulations of the underlying Gross-Pitaevskii equation with a periodic and defect potentials. We also discuss possibilities of driving defect modes through the lattice and suggest ideas for their experimental generation.