Modification of stimulated transition processes of a uniformly moving atom by the presence of a dielectric medium in blackbody radiation

We investigate the effect of the presence of a dielectric medium on the stimulated transition processes of a uniformly moving atom in a thermal radiation field. The cases of atomic subluminal and superluminal motions are considered. The calculated results indicate that the atomic stimulated transition rates depend crucially on the atomic velocity, the temperature of the thermal radiation, the refractive index of medium, and the atomic polarizability. The transition rates are expanded by series in some limiting cases, such as the extreme temperature of thermal radiation, the extreme motion of the atom, and the extremely large refractive index. Our analytical and numerical analyses show that the presence of the dielectric medium has profoundly changed the behaviors and characteristics of the atomic stimulated transition rates, especially when the atom moves faster than the speed of light in the medium. Moreover, the behavior of the transition rates for an atom polarized parallel to the direction of atomic motion is quite distinct from that of an atom polarized perpendicularly to the direction of atomic motion.