Vacuum polarization and pair production in time-dependent electric fields: A quantum-kinetic-equation approach

TL;DR

This paper develops a quantum kinetic equation framework to analyze vacuum polarization and pair production in arbitrary polarized, time-dependent electric fields, providing detailed observable predictions and confirming consistency with previous formalisms.

Contribution

It introduces an improved quantum kinetic equation approach for arbitrary polarization fields and offers detailed analysis of observable quantities in vacuum pair production.

Findings

Computed momentum-resolved particle yields

Analyzed induced electron-positron current and energy-momentum tensor

Confirmed consistency with Dirac-Heisenberg-Wigner formalism

Abstract

The evolution of the vacuum state in a time-dependent external electric field of arbitrary polarization is investigated within a nonperturbative framework of quantum kinetic equations (QKEs). In our previous work [Phys. Rev. Res. 6, 043009 (2024)], a revised version of the QKEs was derived by using an adiabatic basis constructed from one-particle Hamiltonian eigenfunctions in a spatially homogeneous electric field. In this study, we present an extensive analysis of these equations with particular emphasis on observable quantities. Specifically, we compute momentum-resolved particle yields, the induced electron-positron current, the energy-momentum tensor, and the angular-momentum tensor. We also discuss in detail the charge-renormalization procedure required to remove logarithmic divergences. It is shown that our results are consistent with the previous findings obtained via the Dirac-Heisenberg-Wigner formalism. Our analysis provides a firmer theoretical basis for investigations of nonperturbative effects in strong electric fields.