Schwinger Pair Production in Superposed Electric-Field Pulses with Distinct Spatial Widths

Abstract

Electron--positron pair production in spatially and temporally inhomogeneous electric fields is investigated in $1+1$ dimensions within the Dirac--Heisenberg--Wigner (DHW) formalism. We consider a composite field formed by two Gaussian pulses with independently adjustable spatial widths, $λ_1$ and $λ_2$, extending commonly used combined-pulse configurations in which the constituent pulses share the same spatial envelope. Both temporally overlapping and temporally separated configurations are analyzed. For overlapping pulses, decreasing $λ_2$ at fixed $λ_1$ enlarges the weak-field region and enhances the low-momentum part of the particle spectrum. Oscillatory temporal profiles further increase the particle yield while reducing the net momentum transferred to the particles. For temporally separated pulses, the spatial width of the delayed pulse determines the extent to which it accelerates particles created by the earlier pulse. A narrow delayed pulse affects only a limited fraction of these particles, whereas a broader pulse substantially reshapes the final momentum distribution. These results identify the spatial-width disparity between the constituent pulses as an additional control parameter for Schwinger pair production in multicomponent electric fields.