Light Deflection by a Quantum Improved Kerr Black Hole Pierced by a Cosmic String

TL;DR

This paper investigates how quantum corrections and cosmic string topology influence light deflection around a rotating black hole, using geometric and geodesic methods, revealing quantum and topological effects on gravitational lensing.

Contribution

It introduces a novel calculation of light deflection incorporating quantum effects and cosmic string topology in a Kerr black hole spacetime, using the Gauss--Bonnet theorem and geodesic analysis.

Findings

Quantum effects modify the light deflection angle.

Cosmic string topology influences the gravitational lensing.

Consistent results obtained via geometric and geodesic methods.

Abstract

In this work, we calculate the quantum correction effects on the deflection of light in the spacetime geometry of a quantum improved Kerr black hole pierced by an infinitely long cosmic string. More precisely, we calculate the deflection angle by applying the Gauss--Bonnet theorem (GBT) to the osculating optical geometries related to the quantum improved rotating black hole in the weak limit approximation. We find that the deflection angle of light is affected by the quantum effects as well as the global topology due to the presence of the cosmic string. Besides, we have managed to find the same expression for the deflection angle in leading order terms using the geodesic equations.