Dynamically assisted Schwinger effect beyond the spatially-uniform-field approximation

TL;DR

This paper studies electron-positron pair production in strong electric fields with a superimposed fast pulse, going beyond the usual uniform-field approximation to reveal new features in particle spectra and production rates.

Contribution

It introduces a nonperturbative numerical method that accounts for spatial variations of the fast pulse, providing more accurate insights into pair production beyond the dipole approximation.

Findings

Momentum spectra are qualitatively and quantitatively altered.

Total pair production and enhancement factors are reduced.

Spatial dependence significantly impacts pair creation dynamics.

Abstract

We investigate the phenomenon of electron-positron pair production from vacuum in the presence of a strong electric field superimposed by a weak but fast varying pulse which substantially increases the total particle yield. We employ a nonperturbative numerical technique and perform the calculations beyond the spatially-uniform-field approximation, i.e. dipole approximation, taking into account the coordinate dependence of the fast component. The analysis of the main characteristics of the pair-production process (momentum spectra of particles and total amount of pairs) reveals a number of important features which are absent within the previously used approximation. In particular, the structure of the momentum distribution is modified both qualitatively and quantitatively, and the total number of pairs created as well as the enhancement factor due to dynamical assistance become significantly smaller.