Motion-induced energy shifts of a multilevel atom in a black-body radiation field

We investigate the influence of atomic uniform motion on radiative energy shifts of a multilevel atom when it interacts with black-body radiation. Our analysis reveals that the atomic energy shifts depend crucially on three factors: the temperature of black-body thermal radiation, atomic velocity, and atomic polarizability. In the low-temperature limit, the presence of atomic uniform motion always enhances the effect of the thermal field on the atomic energy shifts. However, in the high-temperature limit, the atomic uniform motion enhances the effect of the thermal field for an atom polarizable perpendicular to the atomic velocity but weakens it for an atom polarizable parallel to the atomic velocity. Our work indicates that the physical properties of atom–field coupling systems can in principle be regulated and controlled by the combined action of the thermal field and the atomic uniform motion.

Velocity effect on the stimulated transition process of a multilevel atom in a thermal bath

This paper investigates the stimulated transition process of a uniformly moving atom in interaction with a thermal bath of the quantum electromagnetic field. Using the perturbation theory, the atomic stimulated emission and absorption rates are calculated. The results indicate that the atomic transition rates depend crucially on the atomic velocity, the temperature of the thermal bath, and the atomic polarizability. As these factors change, the atomic stimulated transition processes can be enhanced or weakened at different degrees. In particular, slowly moving atoms in the thermal bath with high temperature ($$T\gg \omega _{0}$$ T ≫ ω 0 ) perceive a smaller effective temperature $$T \big ( 1-\frac{1}{10} v^{2} \big )$$ T ( 1 - 1 10 v 2 ) for the polarizability perpendicular to the atomic velocity or $$T \big ( 1-\frac{3}{10} v^{2} \big )$$ T ( 1 - 3 10 v 2 ) for the polarizability parallel to the atomic velocity. However, ultra-relativistic atoms perceive no influence of the background thermal bath. In turn, in terms of the atomic transition rates, this paper explores and examines the relativity of temperature of the quantum electromagnetic field.

Optical waveguiding by atomic entanglement in multilevel atom arrays

The optical properties of subwavelength arrays of atoms or other quantum emitters have attracted significant interest recently. For example, the strong constructive or destructive interference of emitted light enables arrays to function as nearly perfect mirrors, support topological edge states, and allow for exponentially better quantum memories. In these proposals, the assumed atomic structure was simple, consisting of a unique electronic ground state. Within linear optics, the system is then equivalent to a periodic array of classical dielectric particles, whose periodicity supports the emergence of guided modes. However, it has not been known whether such phenomena persist in the presence of hyperfine structure, as exhibited by most quantum emitters. Here, we show that waveguiding can arise from rich atomic entanglement as a quantum many-body effect and elucidate the necessary conditions. Our work represents a significant step forward in understanding collective effects in arrays of atoms with realistic electronic structure.