Electrodynamics at non-zero temperature, chemical potential, and Bose
  condensate
  Electrodynamics of charged scalar bosons and spin 1/2 fermions is studied at
non-zero temperature, chemical potentials, and possible Bose condensate of the
charged scalars. Debye screening length, plasma frequency, and the photon
dispersion relation are calculated. It is found that in presence of the
condensate the time-time component of the photon polarization operator in the
first order in electric charge squared acquires infrared singular parts
proportional to inverse powers of the spatial photon momentum k.
