Collapse and Revival of the Matter Wave Field of a Bose-Einstein Condensate

Abstract

At the heart of a Bose-Einstein condensate lies its description as a single giant matter wave. Such a Bose-Einstein condensate represents the most "classical" form of a matter wave, just as an optical laser emits the most classical form of an electromagnetic wave. Beneath this giant matter wave, however, the discrete atoms represent a crucial granularity, i.e. a quantization of this matter wave field. Here we show experimentally that this quantization together with the cold collisions between atoms lead to a series of collapses and revivals of the coherent matter wave field of a Bose-Einstein condensate. We observe such collapses and revivals directly in the dynamical evolution of a multiple matter wave interference pattern, and thereby demonstrate a striking new behaviour of macroscopic quantum matter.