Invariant Lagrangian for certain transforms Topics QED Covariant Derivative Noether’s Theory Gauge Transformation Coulomb Gauge Lorenz Gauge (∇2A−μ0ε0∂t2A)−∇(∇⋅A+μ0ε0∂tV)=−μ0J This along with Poisson’s Equation encapsulate Maxwell’s equations