# Horizon Quantum Mechanics of Rotating Black Holes

## TL;DR

This paper extends Horizon Quantum Mechanics to rotating black holes, analyzing their quantum properties and suggesting that certain configurations suppress inner horizons and extremal geometries.

## Contribution

It introduces a formal extension of Horizon Quantum Mechanics to include angular momentum and applies it to a rotating black hole model.

## Key findings

- Inner horizons are suppressed in the model
- Extremal geometries are disfavored
- Rotating black holes exhibit specific quantum features

## Abstract

The Horizon Quantum Mechanics is an approach that was previously introduced in order to analyse the gravitational radius of spherically symmetric systems and compute the probability that a given quantum state is a black hole. In this work, we first extend the formalism to general space-times with asymptotic (ADM) mass and angular momentum. We then apply the extended Horizon Quantum Mechanics to a harmonic model of rotating corpuscular black holes. We find that simple configurations of this model naturally suppress the appearance of the inner horizon and seem to disfavour extremal (macroscopic) geometries.