Atom-atom correlations in spontaneous four wave mixing of two colliding Bose-Einstein Condensates
A. Perrin, Hong Chang, Valentina Krachmalnicoff, M. Schellekens, Denis Boiron, Alain Aspect, Christoph Ira Westbrook
Abstract
We study atom scattering from two colliding Bose-Einstein condensates using a position sensitive, time resolved, single atom detector. In analogy to quantum optics, the process can also be thought of as spontaneous, degenerate four wave mixing of de Broglie waves. We find a clear correlation between atoms with opposite momenta, demonstrating pair production in the scattering process. We also observe a Hanbury Brown and Twiss correlation for collinear momenta, which permits an independent measurement of the size of the pair production source and thus the size of the spatial mode. The back to back pairs occupy very nearly two oppositely directed spatial modes, a promising feature for future quantum optics experiments.