ATOM-FIELD INTERACTIONS - DENSITY-MATRIX EQUATIONS INCLUDING QUANTIZATION OF THE CENTER-OF-MASS MOTION

Master equations are derived for the time evolution of density-matrix elements characterizing atoms interacting with classical radiation fie lds that drive transitions between electronic-state manifolds of level s. The atomic center-of-mass motion is quantized and recoil accompanyi ng absorption, stimulated emission, and spontaneous emission is includ ed. An adiabatic elimination of the optical coherences is used to obta in quantum rate equations for ground- and excited-state density-matrix elements. Subsequent adiabatic elimination of excited-state density-m atrix elements results in rate equations for the slow evolution of gro und-state density-matrix elements. It is shown that recoil during spon taneous emission mixes spatial and internal atomic degrees of freedom.