OBSERVATION OF FLUX ENHANCEMENT IN COLLISIONS BETWEEN ULTRACOLD ATOMS

We have observed a significant cooperative effect in ultracold trap lo ss collisions induced by two separate lasers. One laser, tuned close t o the atomic resonance, excites the atom pair to an attractive potenti al at long range. The resulting acceleration and deflection give rise to an enhancement in the collisional flux of groundstate atoms reachin g short range, as probed by a second laser. Enhancements up to a facto r of similar to 3 have been observed. This indicates that the atomic p air-distribution function can be significantly distorted in a typical laser trap environment.