The growth of a Bose-Einstein condensate: theory vs. experiment

Michael Köhl, Matthew J. Davis, Crispin W. Gardiner +2 more

Guglielmo Maria Tino, M. Inguscio

Crispin W. Gardiner

Summary form only given. Bosonic stimulation as the principal mechanism for the growth of a Bose-Einstein condensate was first introduced and quantitatively evaluated by Gardiner et al., and this was subsequently experimentally verified by Miesner et al. Although agreement between experiment and theory is not perfect, it is clear that the predicted mechanism of stimulated emission into the condensate is indeed the principal cause of condensate growth.

Michael Köhl, Matthew J. Davis, Crispin W. Gardiner +2 more

We report on a quantitative study of the growth process of (87)Rb Bose-Einstein condensates. By continuous evaporative cooling we directly control the thermal cloud from which the condensate grows. We compare the experimental data with the results of a theoretical model based on quantum kinetic theory. We find quantitative agreement with theory for the situation of strong cooling, whereas in the weak cooling regime a distinctly different behavior is found in the experiment.

A. C. Wilson, Callum R. McKenzie

Makoto Yamashita, Masato Koashi, Nobuyuki Imoto

Evaporative cooling of trapped atoms is studied based on the quantum kinetic theory. We extend the classical analysis of Luiten et al. [Phys. Rev. A 53, 381 (1996)] to treat Bose statistics of alkali-metal atoms. Dynamics in evaporative cooling process is described by a kinetic equation for the truncated Bose-Einstein distribution function under the assumption that the system is close to the thermal equilibrium. This approach is applicable to the ``slow'' evaporative cooling normally adopted in most experiments for the efficient production of Bose-Einstein condensates. Time-evolution calculations explain the current experiment well with sodium atoms using a slow evaporative cooling and demonstrate a rapid growth of condensate in the cooling process.