Conceivable helical form of light propagation may signify symmetry   breaking similar to Jahn-Teller effects
  We stress on the similarities between vibronic symmetry-breaking, due to the mixing of electronic states by phonons and leading to vibronic polarons along a helix, and the conceivable helical form of light propagation possibly arising from a symmetry breaking, due to the mixing of fermion states by photons. 
Mladen Georgiev