Optical Theorem in Quantum electrodynamics with Unstable Vacuum
Efim S. Fradkin, Dmitri M Gitman, Sh. M. Shvàrtsman · Fortschritte der Physik/Progress of Physics · 1988
All the results reffering to the relations of the optical theorem in QED with an external electromagnetic field with unstable vacuum are consistently given in this paper. The results obtained are true in all orders of perturbation theory. A generating functional is introduced for calculating total probabilities of any processes in QED with unstable vacuum.