Compactly supported linearised observables in single-field inflation. Issue 7 (25th July 2017)

• Record Type: Journal Article
• Authors: Fröob, Markus B.; Hack, Thomas-Paul; Higuchi, Atsushi
• Is Part Of: Journal of cosmology and astroparticle physics. Volume 2017:Issue 7(2017)
• Page Start: 043
• Page End: 043
• Publication Date: 2017-07-25
• Subjects: cosmological perturbation theory -- quantum field theory on curved space; Cosmology -- Periodicals; Astrophysics -- Periodicals; 523.0105
• DOI: 10.1088/1475-7516/2017/07/043
• Languages: English
• ISSNs: 1475-7516

Abstract

Abstract: 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 gauge-invariant observables such as the linearised Weyl 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.