Large scale magnetic fields from gravitationally coupled electrodynamics
  The generation of primordial magnetic seed fields during inflation is studied
in a theory derived from the one-loop vacuum polarization effective action of
the photon in a curved background. This includes terms which couple the
curvature to the Maxwell tensor. The resulting magnetic field strength is
estimated in a model where the inflationary phase is directly matched to the
standard radiation dominated era. The allowed parameter region is analyzed and
compared with the bounds necessary to seed the galactic magnetic field. It is
found that magnetic fields of cosmologically interesting field strengths can be
generated.
