Ultracold atoms and photons

The interaction of laser light with atoms can be used to cool and trap atomic gases to nanokelvin temperatures, and then to excite and non-invasively study the trapped gas. In our laser cooling and trapping experiments we are able to study quantum phenomena such as Bose-Einstein condensation and reveal subtle oscillations of the condensed atoms. Bose- Einstein condensation can also occur in the photon gas itself, and we study light-matter and light-light interactions in such condensates.