Ultracold collisions

Article By:

Gould, Phillip L. University of Connecticut, Storrs, Connecticut.

Last reviewed:2003

DOI:https://doi.org/10.1036/1097-8542.YB030110

With recent advances in laser cooling and trapping, atoms at temperatures less than 1 millikelvin (that is, one-thousandth of a degree above absolute zero) are now readily available for a variety of applications. These applications range from the production of Bose-Einstein condensates (coherent samples of atoms which behave as macroscopic quantum wavefunctions) to dramatic improvements in atomic clocks. Of particular importance are ultracold collisions, the study of interactions between atoms at these very low temperatures. These processes not only attract fundamental interest but also impact many of the other applications of laser cooling. For example, in a Bose-Einstein condensate the atomic collisional properties determine whether it will be stable or collapse upon itself. In laser-cooled atomic clocks, collisions cause undesirable frequency shifts, limiting their accuracy. Also, several proposed schemes for quantum computation with atoms rely on carefully controlled ultracold collisions. Future work on ultracold collisions will include molecules, where reactions and chemical processes are possible.

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