The Effects of Running Gravitational Coupling On Rotating Black Holes

TL;DR

This paper explores how a running gravitational coupling affects rotating black holes, revealing increased ergospheres, altered horizons, and enhanced energy extraction efficiency compared to classical Kerr black holes.

Contribution

It introduces a novel rotating black hole solution with a running gravitational coupling parameter, analyzing its properties and implications for energy extraction processes.

Findings

Ergosphere size increases with the coupling parameter 

Penrose process efficiency is higher than in Kerr black holes

Horizon and singularity structure are modified by the running coupling

Abstract

In this work we investigate the consequences of running gravitational coupling on the properties of rotating black holes. Apart from the changes induced in the space-time structure of such black holes, we also study the implications to Penrose process and geodetic precession. We are motivated by the functional form of gravitational coupling previously investigated in the context of infra-red limit of asymptotic safe gravity theory. In this approach, the involvement of a new parameter $\tilde{\xi}$ in this solution makes it different from Schwarzschild black hole. The Killing horizon, event horizon and singularity of the computed metric is then discussed. It is noticed that the ergosphere is increased as $\tilde{\xi}$ increases. Considering the black hole solution in equatorial plane, the geodesics of particles, both null and time like cases, are explored. The effective potential is computed and graphically analyzed for different values of parameter $\tilde{\xi}$. The energy extraction from black hole is investigated via Penrose process. For the same values of spin parameter, the numerical results suggest that the efficiency of Penrose process is greater in quantum corrected gravity than in Kerr Black Hole. At the end, a brief discussion on Lense-Thirring frequency is also done.