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Abstract

In this thesis radiative corrections to the probabilities of two basic processes in Quantum Electrodynamics (QED) in the presence of a strong electromagnetic plane wave background field are investigated. The considered two processes are nonlinear Compton scattering (the emission of a single photon by an electron) and nonlinear Breit-Wheeler pair production (the decay of a photon into an electron-positron pair).

Taking radiative corrections into account, the electron, positron, and photon states inside a plane wave are not stable, but "decay" in the sense that electrons and positrons emit photons and photons decay into electron-positron pairs. Employing these states, the probabilities for nonlinear Compton scattering and nonlinear Breit-Wheeler pair production are derived analytically within the local constant field approximation. The particles states decay leads to the appearance of an exponential damping term in those probabilities, limiting them to values below unity even for plane wave pulses with large phase duration and intensity. Afterwards, leading order corrections in the fine-structure constant α to the probability of nonlinear Compton scattering, stemming from the self-interaction of the electron inside a plane wave, are investigated separately. It is shown that those corrections are included in the previously obtained probability within the same approximations.