The optical analogy between a Lorentz-violating cosmos and a magneto-electric medium

The goal of our study is to investigate the effects of Lorentz symmetry violation by examining the behavior of photons within the framework of the Standard Model Extension (SME). We show that, from an optical point of view, the Lorentz-violating cosmos is analogous to a magneto-electric medium like the quantum vacuum in the presence of the magnetic and electric field. This analogy provides a formulation for exploring experimental evidence of Lorentz symmetry violation in the propagation of light in a vacuum, in particular in the case of a radiation background observed like the CMB.