Laser Modification of Ultracold Atomic Collisions in Optical Traps

Intense laser fields in optical neutral-atom traps can have a profound effect on collision cross sections at ultracold temperatures, $T<\mathrm{}{10}^{-3\mathrm{}}$ K. A simple model is developed for the long-range interatomic potentials of two field-dressed atoms. Field dressing ensures that the cross section for associative ionization of two ultracold Na atoms is large in an optical trap, but the cross section is predicted to be about 4 orders of magnitude smaller in optical molasses.