Amplification of local instabilities in a Bose-Einstein condensate with attractive interactions.

We study the collapse of large homogeneous Bose-Einstein condensates due to intrinsic attractive interactions. We observe the amplification of a local instability by seeding a momentum state p and suddenly switching the scattering length negative via a Feshbach resonance. We also observe the appearance of atoms in the conjugate momentum state as required by momentum conservation. For large condensates, the time scale for this depletion process becomes faster than that for global collapse.