Gauge invariance and non-Gaussianity in Inflation

Abstract

We clarify the role of gauge invariance for the computation of quantum non-Gaussian correlators in inflation. A gauge invariant generating functional for n-point functions is given and the special status of the spatially flat gauge is pointed out. We also comment on the relation between gauge transformations, field redefinitions, the choice of $t=\mathrm{const}$ hypersurfaces and the use of boundary terms in computations of non-Gaussianity.

arXiv comment4 pages, no figures; v2: 5 pages, no figures, substantial text added, results unchanged, published in PRD Rapid Communications

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• On the Decoherence of Primordial Gravitons
• An Effective Cosmological Collider
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• Gauge-invariant perturbations at second order in two-field inflation
• Decoherence of Cosmological Perturbations from Boundary Terms and the Non-Classicality of Gravity
• Primordial Non-Gaussianity in Supersolid Inflation
• Why does the effective field theory of inflation work?
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• Scalar Bispectrum Beyond Slow-Roll in the Unified EFT of Inflation
• The Functional Measure for the In-In Path Integral
• Probing Inflation with Precision Bispectra
• The Black Hole Window on Cosmic Inflation