K Burnett, Paul S. Julienne, Paul D. Lett, Eite Tiesinga, Carl J. Williams
Ultra cold atomic collisions have a broad impact in experimental and theoretical atomic physics. These encounters occur in a domain where the quantum mechanical aspects of the interacting particles are manifest, since the de Broglie wavelength is enormous by any normal scale of atomic interactions. Cold collisions permit new types of precision measurements and exquisite control over the quantum dynamics of the cold atomic gas. The properties of Bose-Einstein condensates are determined by a single parameter, which characterized ultra cold collisions, the scattering length. New kinds of high precision spectroscopes using experimentally tunable scattering resonances enable the determination of scattering lengths to high accuracy. Thus, the many-body properties of cold quantum degenerate gases can be modeled without adjustable parameters. One example of such spectroscopy is photoassociation, by which two colliding atoms are optically driven to a dimer molecule state. Photoassociation is also one way to make translationally cold molecules. Some promising uses of quantum control of ultracold atoms interactions may lie in quantum information processing or quantum computing.