Gravity and Electromagnetism with $Y(R)F^2$-type Coupling and Magnetic Monopole Solutions

TL;DR

This paper explores a non-minimal coupling between gravity and electromagnetism via a $Y(R) F^2$ term, deriving field equations and finding magnetic monopole solutions that could explain galaxy rotation curve flatness.

Contribution

It introduces a novel $Y(R) F^2$-type coupling in gravity-electromagnetism theory and derives magnetic monopole solutions with potential astrophysical implications.

Findings

Derived field equations from a first order variational principle.

Found static, spherically symmetric magnetic monopole solutions.

Proposed solutions may explain galaxy rotation curve flatness.

Abstract

We investigate $ Y(R) F^2 $-type coupling of electromagnetic fields to gravity. After we derive field equations by a first order variational principle from the Lagrangian formulation of the non-minimally coupled theory, we look for static, spherically symmetric, magnetic monopole solutions. We point out that the solutions can provide possible geometries which may explain the flatness of the observed rotation curves of galaxies.