Abstract
We have observed Bose-Einstein condensation of pairs of fermionic atoms in an ultracold gas at magnetic fields above a Feshbach resonance, where no stable molecules would exist in vacuum. We accurately determined the position of the resonance to be . Molecular Bose-Einstein condensates were detected after a fast magnetic field ramp, which transferred pairs of atoms at close distances into bound molecules. Condensate fractions as high as 80% were obtained. The large condensate fractions are interpreted in terms of preexisting molecules which are quasistable even above the two-body Feshbach resonance due to the presence of the degenerate Fermi gas.
- Received 1 March 2004
DOI:https://doi.org/10.1103/PhysRevLett.92.120403
©2004 American Physical Society