Observation of flux enhancement in collisions between ultracold atoms

Abstract

We have observed a significant cooperative effect in ultracold trap loss collisions induced by two separate lasers. One laser, tuned close to the atomic resonance, excites the atom pair to an attractive potential at long range. The resulting acceleration and deflection give rise to an enhancement in the collisional flux of ground-state atoms reaching short range, as probed by a second laser. Enhancements up to a factor of ∼3 have been observed. This indicates that the atomic pair-distribution function can be significantly distorted in a typical laser trap environment.