Metastable Bose condensate made of atoms with attractive interaction

Abstract

Recent experiments with trapped cooled atoms have produced evidence for Bose-Einstein condensation (BEC). Among the atoms used are ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, with attractive low-energy interaction. A potential barrier separating the condensed part from the collapse is studied and stability limits are established. The lifetime due to tunneling is estimated and is found to be very small. We further argue that BEC should have significant angular momentum L/N∼1ħ and thus both states with angular momentum ${\mathit{l}}_{\mathit{z}}$=0,1 should be ‘‘macroscopically’’ populated. Eventually, as rotation is slowed down, collapse and strong reheating should occur, in amusing resemblance to a supernova explosion. © 1996 The American Physical Society.