Feynman-gauge photon propagator
= Feynman-gauge photon propagator
{c}
At $\xi=1$, the Euclidean photon propagator is $D_{\mu\nu}(k)=\delta_{\mu\nu}/k^2$. Its Lorentz-index contraction simplifies loop numerators in <quantum electrodynamics>.
= Feynman-gauge photon propagator
{c}
At $\xi=1$, the Euclidean photon propagator is $D_{\mu\nu}(k)=\delta_{\mu\nu}/k^2$. Its Lorentz-index contraction simplifies loop numerators in <quantum electrodynamics>.