Duality Symmetric Electrodynamics in Curved Spacetime

TL;DR

This paper derives a more consistent set of Maxwell equations in curved spacetime, accounting for magnetic charges and the independence of electromagnetic fields from sources, thus extending classical electrodynamics.

Contribution

It introduces a duality symmetric formulation of electrodynamics in curved spacetime, relaxing previous assumptions and incorporating magnetic monopoles.

Findings

Electromagnetic fields in curved spacetime require two pairs of electric and magnetic fields.

The new formulation aligns with the equivalence principle in the presence of magnetic charges.

Standard single-pair description is insufficient in curved spacetime.

Abstract

We derive Maxwell equations for electric and magnetic fields in curved spacetime from first principles, relaxing an unnecessary assumption on the structure of the four-potential inherent to the standard approach and thus restoring the full consistency with the equivalence principle in the following two important cases: first, if the electromagnetic field is considered as a physical entity separate from the charged particles used to measure it, and second, if hypothetical magnetically charged particles are allowed to exist. We find that in a generic curved spacetime, the electromagnetic field has to be described by two pairs of electric and magnetic fields, instead of the only one pair which is enough in the flat spacetime case.