Energy extraction from a Konoplya-Zhidenko rotating non-Kerr black hole

TL;DR

This paper explores how energy can be extracted from a Konoplya-Zhidenko rotating non-Kerr black hole, revealing that deformation parameters significantly influence the ergosphere's properties and the efficiency of the Penrose process.

Contribution

It introduces analysis of energy extraction efficiency in a non-Kerr black hole with deformation parameters, highlighting new features in superspinning cases.

Findings

Ergosphere becomes thinner with increased deformation.

Maximum energy extraction efficiency decreases with deformation for $a<M$.

Efficiency can be nearly unlimited for $a>M$ with positive deformation.

Abstract

We have investigated the properties of the ergosphere and the energy extraction by Penrose process in a Konoplya-Zhidenko rotating non-Kerr black hole spacetime. We find that the ergosphere becomes thin and the maximum efficiency of energy extraction decreases as the deformation parameter increases. For the case with $a<M$, the positive deformation parameter yields that the maximum efficiency is lower than that in the Kerr black hole with the same rotation parameter. However, for the superspinning case with $a>M$, we find that the maximum efficiency can reach so high that it is almost unlimited as the positive deformation parameter is close to zero, which is a new feature of energy extraction in such kind of rotating non-Kerr black hole spacetime.