Dynamically assisted Sauter-Schwinger effect in inhomogeneous electric fields

TL;DR

This paper uses the worldline instanton method to analyze how a weak, time-dependent electric pulse can significantly enhance electron-positron pair creation in a strong inhomogeneous electric field, revealing a threshold effect related to the Keldysh parameters.

Contribution

It provides the first analytic non-perturbative result on the interplay between spatial and temporal inhomogeneities in the Sauter-Schwinger effect, identifying a threshold for enhancement.

Findings

Enhanced pair creation probability when the temporal Keldysh parameter exceeds a critical value.

Identification of a threshold behavior depending on spatial and temporal parameters.

First analytic non-perturbative result for combined spatial-temporal field effects.

Abstract

Via the worldline instanton method, we study electron-positron pair creation by a strong electric field of the profile $E/\cosh^2(kx)$ superimposed by a weaker pulse $E'/\cosh^2(\omega t)$. If the temporal Keldysh parameter $\gamma_\omega=m\omega/(qE)$ exceeds a threshold value $\gamma_\omega^{\rm crit}$ which depends on the spatial Keldysh parameter $\gamma_k=mk/(qE)$, we find a drastic enhancement of the pair creation probability -- reporting on what we believe to be the first analytic non-perturbative result for the interplay between temporal and spatial field dependences $E(t,x)$ in the Sauter-Schwinger effect.