Renormalized charged scalar current on a Reissner-Nordstrom black hole in the presence of charge superradiance

TL;DR

This paper calculates the renormalized charge current of a charged scalar field around a Reissner-Nordstrom black hole, analyzing superradiance effects and backreaction in different quantum states.

Contribution

It introduces a pragmatic mode-sum renormalization method to compute the charge current in superradiant regimes on charged black hole backgrounds.

Findings

Renormalized charge current depends on black hole and scalar field charges.

Superradiance influences the behavior of the quantum charge current.

Backreaction effects are analyzed in the context of the electromagnetic field.

Abstract

We compute the renormalized charge current for a massless, minimally coupled, charged quantum scalar field on a charged Reissner-Nordstrom black hole space-time, using the method of pragmatic mode-sum renormalization. Since the field exhibits superradiance, we consider the past Unruh, Boulware and Candelas-Chrzanowski-Howard states, and study how the renormalized current in these states depends on the charges of the black hole and scalar field. We also study the backreaction of the charge current on the electromagnetic field.