Hawking radiation from spherically symmetrical gravitational collapse to an extremal R-N black hole for a charged scalar field

TL;DR

This paper extends previous work on Hawking radiation from extremal Reissner-Nordström black holes to include charged scalar fields, confirming that such black holes do not radiate particles.

Contribution

It demonstrates that the analysis of Hawking radiation can be adapted for charged scalar fields, reinforcing the non-radiation property of extremal black holes.

Findings

Extremal R-N black holes do not emit Hawking radiation for charged scalar fields.

The analysis method for real scalar fields applies to charged scalar fields with modifications.

Supports the traditional view that extremal black holes are non-radiative.

Abstract

Sijie Gao has recently investigated Hawking radiation from spherically symmetrical gravitational collapse to an extremal R-N black hole for a real scalar field. Especially he estimated the upper bound for the expected number of particles in any wave packet belonging to $\mathcal{H}_{out}$ spontaneously produced from the state $|0>_{in}$, which confirms the traditional belief that extremal black holes do not radiate particles. Making some modifications, we demonstrate that the analysis can go through for a charged scalar field.