On effective mass of a photon in a strong magnetic field
  For the magnetic field in order of the Schwinger critical value or much larger it, the effective mass of a real photon with a preset polarization is investigated in the energy region including two lower creation thresholds of electron and positron on Landau levels. In the high-energy range, when the number of thresholds is large, the quasiclassical approach is used. 
V.M. Katkov
hep-th