Measurements of Collective Collapse in a Bose-Einstein Condensate with Attractive Interactions

The occupation number of a magnetically trapped Bose-Einstein condensate is limited for atoms with attractive interactions. It has been predicted that, as this limit is approached, the condensate will collapse by a collective process. The measured spread in condensate number for samples of ${}^7\mathrm{Li}$ atoms undergoing thermal equilibration is consistent with the occurrence of such collapses.