Blackbody-radiation-induced energy-level shifts for a uniformly moving atom in a dielectric medium

We investigate the influence of the presence of a dielectric medium on the energy shift for a uniformly moving atom in blackbody radiation. The atomic energy-level shift usually depends on the temperature of thermal radiation, the atomic velocity, the refractive index of the medium, and the atomic polarizability. Analytical and numerical analyses indicate that the presence of the dielectric medium has profoundly disturbed the behavior of the atomic energy shifts, especially when the atomic speed is greater than the speed of light in the medium. Our work further suggests that the combination of a medium and atomic relativistic center-of-mass motion can provide insight into the radiative properties of atom-field coupling system.