3 ms·

Where?

• wnoise 4y ago
  in "the magnetic potential is gauge invariant". It differs for different gauges, so is not gauge-invariant, but gauge-dependent. A choice of A _is_ a choice of gauge. The theory using it (i.e. E&M Lagrangian) is what is gauge-invariant. This is a hyper-correction; in practice physicists apply the term in places adjacent to where it should be all the time.
  • Elpis1 4y ago
    Ah, sorry about that! You're right, of course; my brain slipped a bit.