Point splitting renormalization of Schwinger induced current in de Sitter spacetime

TL;DR

This paper presents a covariant, gauge-invariant calculation of the Schwinger-induced current in de Sitter spacetime, confirming IR effects like hyperconductivity as genuine physical phenomena rather than artifacts of renormalization.

Contribution

It introduces a point splitting renormalization method for calculating the current, validating previous results and clarifying the physical nature of IR effects in de Sitter space.

Findings

Current behavior matches previous adiabatic subtraction results

IR hyperconductivity is confirmed as a real IR effect

Negative current in IR regime is a genuine physical phenomenon

Abstract

The covariant and gauge invariant calculation of the current expectation value in the homogeneous electric field in 1+3 dimensional de Sitter spacetime is shown. The result accords with previous work obtained by using adiabatic subtraction scheme. We therefore conclude the counterintuitive behaviors of the current in the infrared (IR) regime such as IR hyperconductivity and negative current are not artifacts of the renormalization scheme, but are real IR effects of the spacetime.