DYNAMICAL EFFECTS IN PAIR PRODUCTION BY ELECTRIC FIELDS

Nonperturbative dynamical effects in fermion-antifermion pair production by classical electric fields are investigated. Following a summary of the results previously given in the literature, a formal connection between fermion pair production in an external field and supersymmetric quantum mechanics is pointed out. Pair production probabilities are calculated in a uniform semiclassical approximation, which yields the Schwinger result in the constant field limit. The multiplicity distributions of the created pairs are shown to be related to the elementary symmetric functions.

UNIFORM SEMICLASSICAL APPROXIMATION FOR ABSORPTIVE SCATTERING SYSTEMS

The uniform semiclassical approximation of the elastic scattering amplitude is generalized to absorptive systems. An integral equation is derived which connects the absorption-modified amplitude to the absorption-free one. Division of the amplitude into diffractive and refractive components is then made possible. Relevance of our formalism to the algebraic approach to scattering theory is pointed out.