MPM code is available at github.com/zeesherman/mutual-polarization Mean-field or Maxwell Garnett effective medium approximation. The meanfield expression given by Maxwell Garnett (i.e., the Maxwell Garnett effective medium approximation) in Table is derived using only the solution to the quasistatic Maxwell's equations for an isolated nanoparticle. The average electric field over the entire volume ⟨E⟩ ≡ E 0 is the weighted sum of the average field in the particles ⟨E p ⟩ and in the fluid ⟨E f ⟩,