Rigorous calculation of heating in alkali-metal traps by background gas collisions - art. no. 033606

The finite depth epsilon of an atom trap results in an upper bound for the energy transfer in collisions with the background gas that will result in h eating but not in loss of an atom. The energy transfer rate is accurately p redicted as function of the well depth by applying a versatile semiempirica l model function for the small-angle differential cross section, covering t he full range from pure diffractive scattering to classical scattering. Sim ple scaling laws for the energy transfer rate are presented that can be rea dily applied. For the diffraction dominated regime we find an energy transf er rate proportional to (epsilon/epsilon(ref))(2) With epsilon(ref) = (k(B) T(b) theta(0)(2/4)), a system-dependent energy determined by the ambient te mperature T-b and the diffraction angle Bo. In the classical regime we find the usual result of an energy transfer rate proportional to (epsilon/epsil on(ref))(5/6).