Cosmological redshift and nonlinear electrodynamics propagation of photons from distant sources

TL;DR

This paper shows that nonlinear electrodynamics modifies the cosmological redshift of photons from distant sources, potentially explaining the universe's accelerated expansion without changing the source's position.

Contribution

It introduces a general framework for how NLED affects photon redshift, revealing a universal correction factor that increases the effective redshift beyond standard predictions.

Findings

Effective redshift is always higher than standard redshift due to NLED effects.

The correction factor depends on magnetic field strength and NLED Lagrangian derivatives.

The source position remains unchanged despite the redshift modification.

Abstract

By-now photons are the unique universal messengers. Cosmological sources like far-away galaxies or quasars are well-known light-emitters. Here we demonstrate that the nonlinear electrodynamics (NLED) description of photon propagation through the weak background intergalactic magnetic fields modifies in a fundamental way the cosmological redshift that a direct computation within a specific cosmological model can abscribe to a distant source. Independently of the class of NLED Lagrangian, the effective redshift turns out to be $1 + \tilde{z} = (1 + z) \Delta$, where $\Delta \equiv (1 + \Phi_e)/(1 + \Phi_o)$, with $\Phi \equiv {8}/{3} ({L_{FF}}/{L_F}) B^2$, being $L_F = {dL}/{dF}$, $L_{FF} = {d^2L}/{dF^2}$, the field $F\equiv F_{\alpha \beta} F^{\alpha \beta}$, and $B$ the magnetic field strength. Thus the effective redshift is always much higher then the standard redshift, but recovers such limit when the NLED correction $\Delta(\Phi_e, \Phi_o) \longrightarrow 1$. This result may provide a physical foundation for the current observation-inspired interpretation that the universe undergoes an accelerate expansion. However, under the situation analyzed here, for any NLED the actual (spatial) position of the light-emitting far-away source remains untouched.