Compactly supported linearised observables in single-field inflation

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We investigate the gauge-invariant observables constructed by smearing the graviton and inflaton fields by compactly supported tensors at linear order in general single-field inflation. These observables correspond to gauge-invariant quantities that can be measured locally. In particular, we show that these observables are equivalent to (smeared) local gaugeinvariant observables such as the linearisedWeyl tensor, which have better infrared properties than the graviton and inflaton fields. Special cases include the equivalence between the compactly supported gauge-invariant graviton observable and the smeared linearised Weyl tensor in Minkowski and de Sitter spaces. Our results indicate that the infrared divergences in the tensor and scalar perturbations in single-field inflation have the same status as in de Sitter space and are both a gauge artefact, in a certain technical sense, at tree level.
Original languageEnglish
Article number043
Number of pages32
JournalJournal of Cosmology and Astroparticle Physics
Issue number7
Publication statusPublished - 25 Jul 2017

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©2017 IOP Publishing Ltd and Sissa Medialab. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details


  • cosmological perturbation theory
  • quantum field theory in curved space
  • quantum field theory on curved space

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