# Charged Einstein-\ae ther black holes in $n$-dimensional spacetime

## TL;DR

This paper explores higher-dimensional charged black holes in Einstein-e6ther theory, analyzing their horizons, surface gravity, and effects of charge and aether parameters across different spacetime geometries.

## Contribution

It extends the study of Einstein-e6ther black holes to higher dimensions, revealing the existence of universal horizons and their properties in various spacetime geometries.

## Key findings

- Universal horizons exist in higher dimensions, trapping particles with arbitrarily large velocities.
- Horizon size decreases and approaches the universal horizon as charge or aether coefficient increases.
- Surface gravity diminishes and approaches zero at extremal charge or high aether coefficient.

## Abstract

In this work, we investigate the $n$-dimensional charged static black hole solutions in the Einstein-\ae ther theory. By taking the metric parameter $k$ to be $1,0$, and $-1$, we obtain the spherical, planar, and hyperbolic spacetimes respectively. Three choices of the cosmological constant, $\Lambda>0$, $\Lambda=0$ and $\Lambda<0$, are investigated, which correspond to asymptotically de Sitter, flat and anti-de Sitter spacetimes. The obtained results show the existence of the universal horizon in higher dimensional cases which may trap any particle with arbitrarily large velocity. We analyze the horizon and the surface gravity of 4- and 5-dimensional black holes, and the relations between the above quantities and the electrical charge. It is shown that when the aether coefficient $c_{13}$ or the charge $Q$ increases, the outer Killing horizon shrinks and approaches the universal horizon. Furthermore, the surface gravity decreases and approaches zero in the limit $c_{13}\rightarrow\infty$ or $Q\rightarrow Q_e$, where $Q_e$ is the extreme charge. The main features of the horizon and surface gravity are found to be similar to those in $n=3$ case, but subtle differences are also observed.