Dynamics of evaporative cooling in magnetically trapped atomic hydrogen
  We study the evaporative cooling of magnetically trapped atomic hydrogen on the basis of the kinetic theory of a Bose gas. The dynamics of trapped atoms is described by the coupled differential equations, considering both the evaporation and dipolar spin relaxation processes. The numerical time-evolution calculations quantitatively agree with the recent experiment of Bose-Einstein condensation with atomic hydrogen. It is demonstrated that the balance between evaporative cooling and heating due to dipolar relaxation limits the number of condensates to 9x10^8 and the corresponding condensate fraction to a small value of 4% as observed experimentally. 
Makoto Yamashita (1), Masato Koashi (2), Tetsuya Mukai (1), Masaharu   Mitsunaga (1) and Nobuyuki Imoto (1 and 2) ((1) NTT B...