Fermi-Pasta-Ulam problem revisited with a Bose-Einstein condensate - art. no. 043601

We consider the evolution of an interacting dilute Bose-Einstein condensate transferred from a harmonic trap to a perfect box of finite size. We study numerically the influence of the nonlinearities in the system on its dynam ics. The parallelism between this problem and the Fermi-Pasta-Ulam problem in the context of matter waves is established. Criteria for the appearance of statistical behavior are discussed. We show that by increasing the nonli nearity we pass from a regime of collapses and revivals for the wave functi on to a regime of collapses and revivals of regular motion.