A Geometrical Approach to Strong Gravitational Lensing in f(R) Gravity

TL;DR

This paper develops a geometric framework for analyzing gravitational lensing in f(R) gravity, deriving equations for null geodesics and bending angles, and applies it to R^n gravity, revealing increased bending compared to general relativity.

Contribution

It introduces a general geometric approach to lensing in f(R) gravity and applies it to specific solutions, highlighting differences from GR.

Findings

More bending occurs in R^n gravity compared to GR.

Bending depends on the parameter n and closest approach distance.

Framework applicable to various f(R) theories.

Abstract

We present a framework for the study of lensing in spherically symmetric spacetimes within the context of f(R) gravity. Equations for the propagation of null geodesics, together with an expression for the bending angle are derived for any f(R) theory and then applied to an exact spherically symmetric solution of R^n gravity. We find that for this case more bending is expected for R^n gravity theories in comparison to GR and is dependent on the value of n and the value of distance of closest approach of the incident null geodesic.