OUTPUT COUPLING AND FLOW OF A DILUTE BOSE-EINSTEIN CONDENSATE

We solve the Gross-Pitaevskii equation to model the behaviour of a wea kly-interacting Bose condensate. Solutions are presented for the eigen states in one- and two-dimensional harmonic traps. We include the effe ct of gravity and coupling to a second condensate to simulate an outpu t coupler for Bose condensed atoms, and find that the output pulse sha pe is in qualitative agreement with experiment. We also model flow und er gravity through a constriction, demonstrating excitation and separa tion of eigenmodes in the condensate.