Resonant emission of hard gamma-quanta at scattering of ultrarelativistic electrons on a nucleus within the external light field

The contemporary theoretical investigation researches the resonant emission of high-energy gamma-quanta within the process of scattering of ultrarelativistic electrons on a nucleus in the external electromagnetic field. With implementation of the resonant conditions under the field ambience the particle in the intermediate state re-modulates into the real form. Therefore, the phenomenon examination determines the functional splitting of the second order process into a pair of first-order effects that possess a possibility to develop within two reaction channels. Consequently, the first channel characterizes the kinematics of electron scattering by a nucleus and following radiation of a spontaneous gamma-quantum. The second channel delineates the spontaneous gamma-quantum radiation by an electron with subsequent scattering on a nucleus. It is important to emphasize that within a specific range of observation the calculations derive three discrete magnitudes for the resonant frequency dependency on the angle of spontaneous photon radiation. As a result, the work represents an estimation of the resonant differential scattering cross-section in ratio to the scattering cross-section computed without the external field. In conclusion, various scientific facilities may verify the project data simulation (SLAC, FAIR, XFEL, ELI, XCELS).

Manipulating thermal emission with spatially static fluctuating fields in arbitrarily shaped epsilon-near-zero bodies

The control and manipulation of thermal fields is a key scientific and technological challenge, usually addressed with nanophotonic structures with a carefully designed geometry. Here, we theoretically investigate a different strategy based on epsilon-near-zero (ENZ) media. We demonstrate that thermal emission from ENZ bodies is characterized by the excitation of spatially static fluctuating fields, which can be resonantly enhanced with the addition of dielectric particles. The “spatially static” character of these temporally dynamic fields leads to enhanced spatial coherence on the surface of the body, resulting in directive thermal emission. By contrast with other approaches, this property is intrinsic to ENZ media and it is not tied to its geometry. This point is illustrated with effects such as geometry-invariant resonant emission, beamforming by boundary deformation, and independence with respect to the position of internal particles. We numerically investigate a practical implementation based on a silicon carbide body containing a germanium rod.