Black Hole Evaporation and Compact Extra Dimensions

TL;DR

This paper investigates how black hole evaporation is affected by extra spatial dimensions, revealing that black holes become more stable as their size approaches the extra dimension scale, with potential phase transitions and remnants.

Contribution

It provides a unified description of black hole evaporation across different size regimes in spacetimes with extra dimensions and predicts a phase transition near the extra dimension scale.

Findings

Luminosity is damped as black hole horizon shrinks towards the extra dimension size.

Black holes smaller than the extra dimension scale are nearly stable.

A possible first-order phase transition with energy outburst and stable remnants.

Abstract

We study the evaporation of black holes in space-times with extra dimensions of size L. We first obtain a description which interpolates between the expected behaviors of very large and very small black holes and then show that the luminosity is greatly damped when the horizon shrinks towards L from a larger value. Analogously, black holes born with an initial size smaller than L are almost stable. This effect is due to the dependence of both the Hawking temperature and the grey-body factor of a black hole on the dimensionality of space. Although the picture of what happens when the horizon becomes of size L is still incomplete, we argue that there occurs a (first order) phase transition, possibly signaled by an outburst of energy which leaves a quasi-stable remnant.