Critical Schwinger pair production

TL;DR

This paper explores the critical behavior of Schwinger pair production in inhomogeneous electric fields, revealing universal scaling laws and classifying backgrounds into universality classes similar to phase transitions.

Contribution

It introduces a framework for understanding pair production near criticality, identifying universality classes and scaling laws based on electric field configurations.

Findings

Pair production rate acts as an order parameter.

Electric backgrounds exhibit universality classes with distinct scaling laws.

Critical exponents depend on large-scale features, not microscopic details.

Abstract

We investigate Schwinger pair production in spatially inhomogeneous electric backgrounds. A critical point for the onset of pair production can be approached by fields that marginally provide sufficient electrostatic energy for an off-shell long-range electron-positron fluctuation to become a real pair. Close to this critical point, we observe features of universality which are analogous to continuous phase transitions in critical phenomena with the pair-production rate serving as an order parameter: electric backgrounds can be subdivided into universality classes and the onset of pair production exhibits characteristic scaling laws. An appropriate design of the electric background field can interpolate between power-law scaling, essential BKT-type scaling and a power-law scaling with log corrections. The corresponding critical exponents only depend on the large-scale features of the electric background, whereas the microscopic details of the background play the role of irrelevant perturbations not affecting criticality.