Universal Statistics of Energy and Information Flow in Random Electromagnetic Fields
We establish a universal statistical description for the local flow of energy and information in random electromagnetic fields. The longitudinal Poynting flux, written as a Hermitian quadratic form of the transverse electric and magnetic field components, follows a probability distribution that is completely determined by four eigenvalues of an electromagnetic covariance matrix. These flux eigenvalues quantify forward transport, optical backflow, and polarization mixing, and reduce to the known paraxial and isotropic limits in the appropriate regimes -- including strongly nonparaxial fields, where no universal description was known so far. Full-vector simulations of continuous and discrete disordered media confirm this universality. The same framework applies to the recently introduced Fisher-information flux, with the fields replaced by their sensitivity to a parameter, thereby unifying the statistics of local energy and information transport in random light and revealing the reversal of information flow across a parameter-dependent object.