WKB approach to pair creation in spacetime-dependent fields

TL;DR

This paper extends the WKB approximation to analyze particle creation in background fields that vary across both space and time, addressing gaps in understanding of such processes in quantum field theory.

Contribution

The authors develop a generalized WKB method for spacetime-dependent fields and demonstrate its application to a spacetime-dependent mass scenario.

Findings

Generalized WKB approach for spacetime-dependent fields

Application to spacetime-dependent mass case

Enhanced understanding of particle creation mechanisms

Abstract

Besides tunneling in static potential landscapes, for example, the Wentzel-Kramers-Brillouin (WKB) approach is a powerful nonperturbative approximation tool to study particle creation due to time-dependent background fields, such as cosmological particle production or the Sauter-Schwinger effect, i.e., electron-positron pair creation in a strong electric field. However, our understanding of particle creation processes in background fields depending on both space and time is rather incomplete. In order to venture into this direction, we propose a generalization of the WKB method to truly spacetime-dependent fields and apply it to the case of a spacetime-dependent mass.