Inflationary Magnetogenesis with Broken Local U(1) Symmetry
  We point out that a successful inflationary magnetogenesis could be realised
if we break the local U(1) gauge symmetry during inflation. The effective
electric charge is fixed as a fundamental constant, which allows us to obtain
an almost scale invariant magnetic spectrum avoiding both the strong coupling
and back reaction problems. We examine the corrections to the primordial
curvature perturbation due to these stochastic electromagnetic fields and find
that, at both linear and non-linear orders, the contributions from the
electromagnetic field are negligible compared to those created from vacuum
fluctuations. Finally, the U(1) gauge symmetry is restored at the end of
inflation.
