Momentum spectra of particles produced in a single pulse of an electric field

Abstract: We study particle creation in a single pulse of an electric field in scalar quantum electrodynamics. We first identify parameter regions of the theory where the dynamical pair creation and Schwinger mechanism respectively dominate each other. Then, analytical expressions for the total characteristics of particle creation are determined for the case where the Schwinger mechanism dominates. We also compare our results with those produced in a constant electric field with a finite-time interval. These results coincide at a strong field regime, however they differ in general field strength. We identify the reason of this difference with a nonperturbative effect of high-frequency photons in external electric fields.