Black Hole Remnants from Dynamical Dimensional Reduction?

TL;DR

This paper investigates how the reduction of spectral dimension at microscopic scales affects black hole evaporation, showing it makes luminosity finite but does not produce long-lived remnants.

Contribution

It analyzes the impact of dynamical spectral dimension reduction on black hole Hawking radiation and its implications for black hole remnants.

Findings

Black hole luminosity becomes finite due to spectral dimension reduction.

The mechanism slightly extends the lifetime of small black holes.

Long-lived black hole remnants are not generated by this process.

Abstract

A intriguing feature shared by many quantum gravity programs is the dynamical decrease of the spectral dimension from $D_s = 4$ at macroscopic to $D_s \approx 2$ at microscopic scales. In this note, we study the impact of this transition on the energy loss of static, spherically symmetric black holes due to Hawking radiation. We demonstrate that the decrease in the spectral dimension renders the luminosity of a black hole finite. While this slightly increases the life-time of light black holes, we find that this mechanism is insufficient to generate long-lived black hole remnants. We briefly comment on the relation of our findings to previous work on this topic.