  We study classical lattice simulations of theories of electrodynamics coupled
to charged matter at finite temperature, interpreting them using the
higher-form symmetry formulation of magnetohydrodynamics (MHD). We compute
transport coefficients using classical Kubo formulas on the lattice and show
that the properties of the simulated plasma are in complete agreement with the
predictions from effective field theories. In particular, the higher-form
formulation allows us to understand from hydrodynamic considerations the
relaxation rate of axial charge in the chiral plasma observed in previous
simulations. A key point is that the resistivity of the plasma -- defined in
terms of Kubo formulas for the electric field in the 1-form formulation of MHD
-- remains a well-defined and predictive quantity at strong electromagnetic
coupling. However, the Kubo formulas used to define the conventional
conductivity vanish at low frequencies due to electrodynamic fluctuations, and
thus the concept of the conductivity of a gauged electric current must be
interpreted with care.

High Energy Physics - Theory;High Energy Physics - Lattice;High Energy Physics - Phenomenology