Physical Review Letters
The point of instability of a Bose-Einstein condensate (BEC) due to attractive interactions was studied. Stable 85Rb BECs were created and then caused to collapse by slowly changing the atom-atom interaction from repulsive to attractive using a Feshbach resonance. At a critical value, an abrupt transition was observed in which atoms were ejected from the condensate. By measuring the onset of this transition as a function of number and attractive interaction strength, we determined the stability condition to be N|a|/aho=0.459±0.012±0.054, slightly lower than the predicted value of 0.574.
Roberts, Jacob L.; Claussen, Neil R.; Cornish, Simon L.; Donley, Elizabeth A.; Cornell, Eric A.; and Wieman, Carl E., "Controlled Collapse of a Bose-Einstein Condensate" (2001). Physics Faculty Contributions. 8.