Effective electromagnetic theory for dielectric media
  Light in a dielectric medium moves slower than in vacuum. The corresponding electromagnetic field equations are then no longer invariant under ordinary Lorentz transformations, but only under such transformations corresponding to this reduced velocity. Based on this physical symmetry, an effective theory for low-energy electromagnetic phenomena in dielectrics is constructed. It has none of the problems of the old formulations of Minkowski and Abraham. Dispersion in the optical regime and the Kerr effect arise in a natural way from higher order interaction terms. The effective field theory is quantized by standard methods and quantum corrections can be calculated in a systematic way. Thus it relates many different classical and quantum optical phenomena into a unified description. 
Finn Ravndal