Semiclassical geons as solitonic black hole remnants

TL;DR

This paper proposes that black hole evaporation could end with stable, non-singular solitonic remnants that resemble geons, potentially contributing to dark matter and primordial black hole understanding.

Contribution

It introduces a new class of stable, non-singular black hole remnants modeled as geons within a semiclassical Palatini gravity framework, avoiding instabilities of traditional quadratic gravity.

Findings

Remnants are non-singular, horizonless, stable geons with Planck-scale masses.

These objects mimic charged black holes but are source-free and contain wormholes.

Potential implications for primordial black holes and dark matter are discussed.

Abstract

We find that the end state of black hole evaporation could be represented by non-singular and without event horizon stable solitonic remnants with masses of the order the Planck scale and up to 16 units of charge. Though these objects are locally indistinguishable from spherically symmetric, massive electric (or magnetic) charges, they turn out to be sourceless geons containing a wormhole generated by the electromagnetic field. Our results are obtained by interpreting semiclassical corrections to Einstein's theory in the first-order (Palatini) formalism, which yields second-order equations and avoids the instabilities of the usual (metric) formulation of quadratic gravity. We also discuss the potential relevance of these solutions for primordial black holes and the dark matter problem.