Hawking Radiation as Tunneling for Extremal and Rotating Black Holes

TL;DR

This paper revisits semi-classical tunneling methods for Hawking radiation, applying them to rotating and extremal black holes, and clarifies the temperature predictions, contrasting with Euclidean approaches.

Contribution

It extends tunneling methods to rotating and extremal black holes, showing they predict zero temperature for extremal cases, contrasting with Euclidean methods.

Findings

Tunneling method sets extremal black hole temperature to zero.

Euclidean method allows arbitrary temperature for extremal black holes.

Comparison highlights differences between semi-classical and Euclidean approaches.

Abstract

The issue concerning semi-classical methods recently developed in deriving the conditions for Hawking radiation as tunneling, is revisited and applied also to rotating black hole solutions as well as to the extremal cases. It is noticed how the tunneling method fixes the temperature of extremal black hole to be zero, unlike the Euclidean regularity method that allows an arbitrary compactification period. A comparison with other approaches is presented.