THEORY OF COLLISIONS BETWEEN LASER COOLED ATOMS

This chapter presents the theory of collisions among laser-cooled atoms. Laser cooling techniques offer many new opportunities for science and technology, including greatly improved time and frequency standards and the ability to study the very novel physics that characterize the collisions of such cold atoms. It is important to understand ultracold collisions for two reasons. First, collisions in a trap can limit the trap lifetime or otherwise degrade the performance of a desired application. Second, ultracold collisions exhibit new and unusual effects that are interesting in themselves. The collisions of cooled and trapped neutral atoms have been studied experimentally and theoretically. In addition, two different methods of observing the collisions of trapped atoms have been used so far. One is to stop loading the trap and watch the trap density decay because of processes that eject atoms from the trap. The other method is to observe the appearance rate of products of a collision, as done for Na+ ions produced by associative ionization (AI) of two excited Na atoms. © 1993, Academic Press Inc.