Electrodynamics with Lorentz-violating operators of arbitrary dimension

Understand

The behavior of photons in the presence of Lorentz and CPT violation is studied.

• Allowing for operators of arbitrary mass dimension, we classify all gauge-invariant Lorentz- and CPT-violating terms in the quadratic Lagrange density associated with the effective photon propagator.
• The covariant dispersion relation is obtained, and conditions for birefringence are discussed.
• We provide a complete characterization of the coefficients for Lorentz violation for all mass dimensions via a decomposition using spin-weighted spherical harmonics.