Derivation of the Electromagnetic Wave Energy Density Formula

Within the framework of World Quantum Theory (WQT), this paper derives the electromagnetic wave energy density formula starting from the particle's static energy Em and dynamic energy Ep. The electric field energy density is derived from static energy: u_E = Em / Volume = (1/2)·ε_m·E² The magnetic field energy density is derived from dynamic energy: u_B = Ep / Volume = B²/(2μ_p) The final formula: u = u_E + u_B = (1/2)·ε_m·E² + B²/(2μ_p) This is formally consistent with the standard physics formula (which is written with ε₀, μ₀). But the starting point is different: standard physics starts from macroscopic models (capacitor, inductor), while this paper starts from the particle's own energy structure. The standard physics derivation relies on five unstated implicit premises; the derivation in this paper does not require these premises. Keywords: electromagnetic wave energy density, static energy, dynamic energy, implicit premises, derivation