Inflation in a scale invariant universe

Pedro G. Ferreira, Christopher T. Hill, Johannes Noller, Graham G. Ross

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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.
Original languageEnglish
Article number123516
Pages (from-to)1-11
Number of pages11
JournalPhysical Review D
Issue number12
Early online date13 Jun 2018
Publication statusPublished - 15 Jun 2018


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