Dynamics of Bose-Einstein condensation in a gas with attractive interactions

The nature of Bose-Einstein condensation (BEC) in atomic vapours depends cr itically on the mean-field interaction of the atoms. When this interaction is attractive, the number of atoms in the condensate is limited. The interp lay of this limit and the natural growth of the condensate during BEC leads to complicated dynamical behaviour. We develop a model for this behaviour based on the nonlinear Schrodinger equation and the quantum Boltzmann equat ion. The condensate occupation number is predicted to oscillate rapidly as the condensate alternately fills and collapses, and the oscillations are se en to persist for many cycles before the gas comes to equilibrium. Experime ntal evidence for these oscillations in the case of Li-7 is presented, alon g with details of the experimental apparatus and methods.