(1/(c^2)) ((∂^2)/(∂(t^2)))   ψ-(∇^2)ψ-(∇^2)ψ+(((m^2)(c^2))/(ℏ^2))ψ=0

H(t)|ψ(t)⟩=iℏ (d/dt)|ψ(t)⟩