Perturbative interactions in scalar electrodynamics
= Perturbative interactions in scalar electrodynamics
{title2=$D_\mu=\partial_\mu+ieA_\mu$}
Expanding the covariant kinetic term of <scalar electrodynamics> gives a one-photon two-scalar vertex and a two-photon two-scalar <seagull vertex>. Their tree amplitudes and <Ward identities> depend on a consistent choice of charge-flow and <gauge covariant derivative> convention.