Vortices in Black Holes

TL;DR

This paper proposes that black holes have vortex structures, linking their extremality and stability to vorticity, and suggests observable consequences like jet formation and flux entrapment that could reveal hidden sectors.

Contribution

It introduces the concept of vortex structures in black holes, connecting graviton condensates and saturons to explain extremality and stability, and explores observable signatures.

Findings

Black holes can be modeled as vortex structures with vorticity.

Vorticity explains extremal spin and stability against Hawking evaporation.

Magnetic flux entrapment by vortices can produce observable astrophysical phenomena.

Abstract

We argue that black holes admit vortex structure. This is based both on a graviton-condensate description of a black hole as well as on a correspondence between black holes and generic objects with maximal entropy compatible with unitarity, so-called saturons. We show that due to vorticity, a $Q$-ball-type saturon of a calculable renormalizable theory obeys the same extremality bound on the spin as the black hole. Correspondingly, a black hole with extremal spin emerges as a graviton condensate with vorticity. This offers a topological explanation for the stability of extremal black holes against Hawking evaporation. Next, we show that in the presence of mobile charges, the global vortex traps a magnetic flux of the gauge field. This can have macroscopically-observable consequences. For instance, the most powerful jets observed in active galactic nuclei can potentially be accounted for. As a signature, such emissions can occur even without a magnetized accretion disk surrounding the black hole. The flux entrapment can provide an observational window to various hidden sectors, such as millicharged dark matter.