Symmetries from Locality. I. Electromagnetism and Charge Conservation

Understand

It is well known that a theory of the (i) Lorentz invariant and (ii) locally interacting (iii) two degrees of freedom of a massless spin 1 particle, the photon, leads uniquely to electromagnetism at large distances.

• In this work, we remove the assumption of (i) Lorentz boost invariance, but we still demand (ii) and (iii).
• We consider several broad classes of theories of spin 1, which in general explicitly violate Lorentz symmetry.
• We restrict to the familiar two degrees of freedom of the photon.