Fixed Scalars and Suppression of Hawking Evaporation

TL;DR

This paper investigates how fixed scalars in extremal charged black holes influence Hawking radiation, revealing a suppression effect near extremality and calculating specific absorption cross sections.

Contribution

It introduces the concept of fixed scalars in extremal black holes and computes their impact on Hawking radiation suppression.

Findings

Absorption cross section proportional to the square of frequency.

Hawking radiation is strongly suppressed near extremality.

Calculated specific proportionality coefficient for a model.

Abstract

For an extreme charged black hole some scalars take on a fixed value at the horizon determined by the charges alone. We call them fixed scalars. We find the absorption cross section for a low frequency wave of a fixed scalar to be proportional to the square of the frequency. This implies a strong suppression of the Hawking radiation near extremality. We compute the coefficient of proportionality for a specific model.