# Cosmic censorship violation in black hole collisions in higher dimensions

## TL;DR

This paper demonstrates that in higher-dimensional spacetimes, black hole collisions with high angular momentum can lead to a violation of cosmic censorship, forming unstable horizons and diverging curvatures, with minimal loss of predictability.

## Contribution

It shows that cosmic censorship can be violated in high-dimensional black hole collisions, using effective theory simulations and analyzing the suppression of gravitational radiation.

## Key findings

- Black hole collisions in high dimensions can produce unstable horizons.
- Diverging curvature occurs during the formation of a neck in the horizon.
- Loss of predictability remains small despite censorship violation.

## Abstract

We argue that cosmic censorship is violated in the collision of two black holes in high spacetime dimension D when the initial total angular momentum is sufficiently large. The two black holes merge and form an unstable bar-like horizon, which grows a neck in its middle that pinches down with diverging curvature. When D is large, the emission of gravitational radiation is strongly suppressed and cannot spin down the system to a stable rotating black hole before the neck grows. The phenomenon is demonstrated using simple numerical simulations of the effective theory in the 1/D expansion. We propose that, even though cosmic censorship is violated, the loss of predictability is small independently of D.