Coulomb gauge

Summary

The Coulomb gauge is the gauge fixing condition that the magnetic vector potential has zero divergence. In this gauge the scalar potential is the instantaneous Coulomb potential of the charge distribution, found from Poisson's equation. The vector potential is then purely transverse, which suits magnetostatics, radiation in the absence of charges and the quantization of the electromagnetic field. Unlike the Lorenz gauge, it singles out a frame of reference.