Inflation in a scale invariant universe
  A scale-invariant universe can have a period of accelerated expansion at
early times: inflation. We use a frame-invariant approach to calculate
inflationary observables in a scale invariant theory of gravity involving two
scalar fields - the spectral indices, the tensor to scalar ratio, the level of
isocurvature modes and non-Gaussianity. We show that scale symmetry leads to an
exact cancellation of isocurvature modes and that, in the scale-symmetry broken
phase, this theory is well described by a single scalar field theory. We find
the predictions of this theory strongly compatible with current observations.
