Propagation of light in area metric backgrounds

TL;DR

This paper investigates how light propagates in area metric spacetimes, revealing that light rays follow Finslerian geodesics and providing experimental bounds on spacetime non-metricity.

Contribution

It demonstrates that light in area metric backgrounds follows Finslerian geodesics and derives observational bounds on non-metricity in the solar system.

Findings

Light rays follow Finslerian geodesics in area metric spacetimes.

Derived experimental bounds on spacetime non-metricity.

Analyzed light deflection in spherically symmetric area metric backgrounds.

Abstract

The propagation of light in area metric spacetimes, which naturally emerge as refined backgrounds in quantum electrodynamics and quantum gravity, is studied from first principles. In the geometric-optical limit, light rays are found to follow geodesics in a Finslerian geometry, with the Finsler norm being determined by the area metric tensor. Based on this result, and an understanding of the non-linear relation between ray vectors and wave covectors in such refined backgrounds, we study light deflection in spherically symmetric situations, and obtain experimental bounds on the non-metricity of spacetime in the solar system.