Dynamics of a Bose condensate with attractive interactions

Summary form only given.One approach to experimentally verifying that collapses occur is to nonperturbatively observe the gas and monitor N, over time. In principle, phase-contrast imaging techniques can be used to make such observations, by illuminating the cloud with a weak, far-detuned probe laser. However, because l, is relatively small, a probe that is sufficiently weak to avoid perturbing the atoms does not provide a large enough signal to accurately determine N,. This difficulty can be circumvented by sacrificing imaging resolution and measuring instead the total number of trapped atoms in the cloud. Collapses are then detected as discontinuous drops in the signal. We have implemented this detection scheme and are attempting to observe collapses and measure their frequency.