Nonlinear electrodynamics and the variation of the fine structure constant

TL;DR

This paper explores how nonlinear electrodynamics can explain conflicting observations of the fine structure constant's variation over cosmic time, reconciling different experimental results through photon interactions with magnetic fields.

Contribution

It proposes a nonlinear electrodynamics framework to interpret variations in the fine structure constant, aligning diverse observational claims with theoretical models.

Findings

NLED can reconcile conflicting measurements of $\alpha$ variation.

Photon interactions with magnetic fields influence the observed $\alpha$ changes.

NLED predictions are consistent with Oklo reactor constraints.

Abstract

It has been claimed that during the late time history of our universe, the fine structure constant of electromagnetism, $\alpha$, has been increasing (Webb et al. 2001; Murphy et al. 2003). The conclusion is achieved after looking at the separation between lines of ions like CIV, MgII, SiII, FeII, among others in the absorption spectra of very distant quasars, and comparing them with their counterparts obtained in the laboratory. However, in the meantime, other teams has claimed either a null result or a decreasing $\alpha$ with respect to the cosmic time (Chand et al. 2004; Levshakov et al. 2004). Also, the current precision of laboratory tests does not allow one to either comfort or reject any of these astronomical observations. Here we suggest that as photons are the sidereal messengers, a nonlinear electrodynamics (NLED) description of the interaction of photons with the weak local background magnetic fields of a gas cloud absorber around the emitting quasar can reconcile the Chand et al. (2004) and Levshakov et al. (2004) findings with the negative variation found by Murphy et al. (2001a, 2001b, 2001c, 2001d) and Webb et al. (2001), and also to find a bridge with the positive variation argued more recently by Levshakov et al. (2006a, 2007). We also show that nonlinear electrodynamics photon propagation in a vacuum permeated by a background magnetic field presents a full agreement with constraints from Oklo natural reactor data. Finally, we show that NLED may render a null result only in a narrow range of the local background magnetic field which should be the case of both the claims by Chand et al.(2004) and by Srianand et al. (2004).