Abstract
We present a method of adiabatically changing the local phase-space density of an ultracold gas using a combination of magnetic and optical forces. Applying this method, we observe phase-space density increases in a gas of sodium atoms by as much as 50-fold. The transition to Bose-Einstein condensation was crossed reversibly, attaining condensate fractions of up to . Measurements of the condensate fraction reveal its reduction due to interactions.
- Received 1 May 1998
DOI:https://doi.org/10.1103/PhysRevLett.81.2194
©1998 American Physical Society