Energy Extraction from Higher Dimensional Black Holes and Black Rings

TL;DR

This paper investigates energy extraction via the Penrose process in higher-dimensional black holes and black rings, revealing higher efficiencies and stability characteristics distinct from four-dimensional cases.

Contribution

It demonstrates that energy extraction efficiency can be significantly higher in higher dimensions and analyzes the stability of black rings using catastrophe theory.

Findings

Efficiency can be infinitely large when one rotation parameter vanishes.

Higher-dimensional black holes and rings exhibit greater energy extraction efficiency.

Black rings with higher rotational energy are unstable, indicating a new instability type.

Abstract

We analyze the energy extraction by the Penrose process in higher dimensions. Our result shows the efficiency of the process from higher dimensional black holes and black rings can be rather high compared with than that in four dimensional Kerr black hole. In particular, if one rotation parameter vanishes, the maximum efficiency becomes infinitely large because the angular momentum is not bounded from above. We also apply a catastrophe theory to analyze the stability of black rings. It indicates a branch of black rings with higher rotational energy is unstable, which should be a different type of instability from the Gregory-Laflamme's one.