The Weak Gravity Conjecture Requires the Existence of Exotic AdS Black Holes

TL;DR

The paper argues that the Weak Gravity Conjecture implies the existence of exotic extremal AdS black holes with angular horizons, expanding the understanding of black hole decay processes in AdS spaces.

Contribution

It demonstrates that the Weak Gravity Conjecture necessitates the existence of exotic AdS black holes with angular horizons for their decay, a novel insight into black hole physics.

Findings

Exotic AdS black holes with angular horizons are required by the conjecture.

Stable extremal AdS black holes can decay via emission of these exotic black holes.

The results connect the Weak Gravity Conjecture to new black hole solutions in AdS space.

Abstract

The Weak Gravity Conjecture arises from the requirement that it be possible for all (classically stable) extremal black holes to decay. The ``black hole version'' of the conjecture requires that it should be possible for this to occur through the emission of smaller black holes. We consider this version in the case of extremal AdS$_4$-Kerr-Newman black holes which are stable against a superradiant instability. One finds that the emitted black hole must be rather exotic, having an ``angular horizon'' analogous to the more familiar (radial) horizon.