Spontaneous Lorentz symmetry breaking in nonlinear electrodynamics

TL;DR

This paper reviews a model of nonlinear electrodynamics where spontaneous Lorentz symmetry breaking occurs due to a nonzero vacuum electromagnetic tensor, leading to anisotropic light propagation and tight experimental bounds.

Contribution

It introduces a gauge invariant model of spontaneous Lorentz symmetry breaking with specific predictions on light anisotropy and stability in the small violation regime.

Findings

Speed of light remains frequency-independent.

One propagating mode exhibits high anisotropy.

Experimental bound on anisotropy is (Δc)/c < 10^{-32}.

Abstract

We review some of the basic features and predictions of a gauge invariant spontaneous Lorentz symmetry breaking model arising from the nonzero vacuum expectation value of the electromagnetic tensor and leading to a nonlinear electrodynamics. The model is stable in the small Lorentz invariance violation approximation. The speed of light is independent of the frequency and one of the propagating modes is highly anisotropic. The bound (Delta c)/c < 10^{-32} is obtained for such anisotropy measured in perpendicular directions.