Coupled inflaton and electromagnetic fields from Gravitoelectromagnetic
  Inflation with Lorentz and Feynman gauges
  Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we
study the origin and evolution of seminal inflaton and electromagnetic fields
in the early inflationary universe from a 5D vacuum state. We use
simultaneously the Lorentz and Feynman gauges. Our formalism is naturally not
conformal invariant on the effective 4D de Sitter metric, which make possible
the super adiabatic amplification of electric and magnetic field modes during
the early inflationary epoch of the universe on cosmological scales. This is
the first time that solutions for the electric field fluctuations are
investigated in a systematic way as embeddings for inflationary models in 4D.
An important and new result here obtained is that the spectrum of the electric
field fluctuations depend with the scale, such that the spectral index
increases quadratically as the scale decreases.
