Stability of exact solutions of the defocusing nonlinear Schrödinger equation with periodic potential in two dimensions
Bernard Deconinck, Béla A. Frigyik, J. Nathan Kutz
Abstract
The cubic nonlinear Schrodinger equation with repulsive nonlinearity and elliptic function potential in two-dimensions models a repulsive dilute gas Bose--Einstein condensate in a lattice potential. A family of exact stationary solutions is presented and its stability is examined using analytical and numerical methods. All stable trivial-phase solutions are off-set from the zero level. Our results imply that a large number of condensed atoms is sufficient to form a stable, periodic condensate. Key words: Bose-Einstein condensates, two-dimensional nonlinear Schrodinger equation, periodic potential, elliptic functions PACS: 65.65 1 Introduction The cubic nonlinear Schrodinger equation with attractive or repulsive nonlinearity and a potential is used as a mean-field model for the dynamics of a dilute-gas Bose Einstein condensate (BEC) [1,2]. In this case, the equation is often referred to as the Gross-Pitaevskii equation. These BECs are of interest in both the theoretical and experim...