Accelerated expansion in the effective field theory of a radiation
  dominated universe
  We construct the effective field theory of a perfect fluid in the early
universe. Focusing on the case where the fluid has the equation of state of
radiation, we show that it may lead to corrections to the background dynamics
that can dominate over those of an effective field theory of gravity alone. We
describe the periods of accelerated expansion, in the form of inflationary and
bounce solutions, that arise in the background dynamics and discuss their
regime of validity within EFT.
