Griffiths Introduction to Elementary Particles · Problem 7.20

Electrodynamics of Quarks and Hadrons — David J. Griffiths

Physics — QFT · gauge-invariance-coulomb-gauge

Problem

Show that we are always free to pick

A^0 = 0

, in free space [eq. (7.85)]. [That is, given a potential

A^\mu

which does not satisfy this constraint, find a gauge function

\lambda

, consistent with equation (7.84), such that

A_0'

, in equation (7.81), is zero.]