Semiclassical theory of field-induced thermal transition rate with application to output coupling of a Bose-Einstein gas at finite temperature

The transfer rate of a thermal distribution of atoms or molecules between two potential surfaces under the influence of an external electromagnetic field was approximated. The method was applied to the case of weak output coupling of a magnetically trapped atomic Bose-Einstein gas at finite temperature to obtain quantitative predictions for the spectrum of transition rates in real situations. Results showed an asymmetric broadening of the spectrum of transitions relative to the expected spectrum of transitions at zero temperature.