The deviation factor and divergences in quantum electrodynamics, concrete examples.

We consider the divergences in quantum electrodynamics. Our approach is based on ideas from the theory of generalized wave operators. In particular, we use the concept of the deviation factor. The deviation factor characterizes the deviations of the initial and final waves from the free waves. The approach is demonstrated on important examples. • We present a new approach to the divergence problems, which is based on the theory of generalized wave operators. • Our approach essentially differs from the well-known Kulish-Faddeev approach. The scattering operator commutes in our case with the unperturbed operator. • The nonstationary Schrödinger and Dirac equations with Coulomb-type potentials are studied rigorously. In Dirac equation case, the results are new. • We use our deviation factor approach to interpret rigorously several important examples from the Akhiezer–Berestetskii and Pokorski books. • We show also that our approach may be used in the 4- ε dimensional case. [ABSTRACT FROM AUTHOR]