Solutions for f(R) gravity coupled with electromagnetic field

TL;DR

This paper derives solutions for f(R) gravity coupled with electromagnetic fields, revealing non-asymptotically flat black holes with deficit angles and connecting to global monopole solutions, highlighting the effects of nonlinear electromagnetic sources.

Contribution

It provides new exact solutions for f(R) gravity with electromagnetic fields, including non-asymptotically flat black holes and monopole limits, expanding understanding of modified gravity models.

Findings

Black holes are non-asymptotically flat with deficit angles.

Solutions include the global monopole in f(R) gravity.

Nonlinear electromagnetic sources influence black hole mass sign.

Abstract

In the presence of external, linear / nonlinear electromagnetic fields we integrate f(R) \sim R+2{\alpha}\surd(R+const.) gravity equations. In contrast to their Einsteinian cousins the obtained black holes are non-asymptotically flat with a deficit angle. In proper limits we obtain from our general solution the global monopole solution in f(R) gravity. The scale symmetry breaking term adopted as the nonlinear electromagnetic source adjusts the sign of the mass of the resulting black hole to be physical.