The Entropic Vacuum

This paper presents a phenomenological extension of classical electrodynamics in which the vacuum is modeled as an emergent structured medium described by a scalar order parameter coupled to electromagnetic fields. The framework preserves gauge invariance while predicting experimentally testable effects including temperature-dependent vacuum birefringence, modified electromagnetic propagation, and delayed resonant electromagnetic emission. The model is formulated as an effective field theory intended to explore possible mesoscopic vacuum dynamics beyond standard electrodynamics.