STUDYING BOSE EINSTEIN CONDENSATION IN HYDROGEN
Because the energy levels in hydrogen are so widely spaced, probing the properties of hydrogen as it proceeds into a Bose-Einstein condensation (BEC) state requires the presence of two photons. When the frequency of the laser is exactly half of the natural frequency of the atomic hydrogen (the 1S-2S transition), two photons are absorbed by an atom (part of a cloud of atoms held in an atom trap). The atom subsequently emits a single ultraviolet ("Lyman-alpha") photon which is observed by a detector at low temperature. Because the hydrogen frequency is density dependent, a sudden shift in the frequency indicates the formation of the high density BEC condensate. (Courtesy of MIT) This research is reported by researchers at MIT.