Imprints of rastall gravity on particle dynamics

Abstract

In this paper, we investigate the trajectories of test particle around the Kerr-Newman anti de-Sitter black hole enclosed by scalar field matter in the context of Rastall gravity. We limit our research to the equatorial plane and analyze the dynamics of both null as well as time-like geodesics. We explore the stable regions with respect to the event horizon, radius of photon orbit and the so called static radius for both null as well as time-like particles. We found that the stable point is always less than the cosmological horizon as well as the static radius. We also discuss the energy extraction as well as negative energy state via Penrose process. The efficiency of the process from Kerr-Newman anti de-Sitter black hole is also examined. We observe that the efficiency of the Penrose process increased with the spin parameter as well the intensity of the scalar field around the BH.