Panagiotis Mavrogiannis (Aristotle University of Thessaloniki, Greece)

Gravito-electromagnetic equivalence on large scales

We revisit the problem of the relativistic coupling between gravity and electromagnetism. In particular, we put into question the status of electromagnetism on large scales, whether it behaves as a source or as a form of gravity. Considering a metric-affine framework and a simple action principle, we find out that a component of gravity, the so-called homothetic curvature field, satisfies both sets of Maxwell equations. Therefore, we arrive at a gravito-electromagnetic equivalence analogous to the mass-energy equivalence. We raise and discuss some crucial questions implied by the aforementioned finding concerning the way we envisage electromagnetism on large scales.