Bounds on non-adiabatic evolution in single-field inflation

Abstract

We examine the regime of validity of $N$-point spectra predictions of single field inflation models that invoke transient periods of non-adiabatic evolution. Such models generate oscillatory features in these spectra spanning frequencies up to the inverse time scale of the transient feature. To avoid strong coupling of fluctuations in these theories this scale must be at least $\sim 10^{-2}/c_s$ of the Hubble time during inflation, where $c_s$ is the inflaton sound speed. We show that, in such models, the signal-to-noise ratio of the bispectrum is bounded from above by that of the power spectrum, implying that searches for features due to non-adiabatic evolution are best focussed first on the latter.

14 pages, no figures

References in corpus (14)

• The Effective Field Theory of Inflation
• Monodromy in the CMB: Gravity Waves and String Inflation
• Generation and Characterization of Large Non-Gaussianities in Single Field Inflation
• On the consistency relation of the 3-point function in single field inflation
• The shape of primordial non-Gaussianity and the CMB bispectrum
• Inflation and WMAP three year data: Features have a Future!
• Heavy fields, reduced speeds of sound and decoupling during inflation
• CMB polarization features from inflation versus reionization
• Strongly Coupled Perturbations in Two-Field Inflationary Models
• New Constraints on Oscillations in the Primordial Spectrum of Inflationary Perturbations
• Folded Resonant Non-Gaussianity in General Single Field Inflation
• Simple Bounds from the Perturbative Regime of Inflation
• Strong scale dependent bispectrum in the Starobinsky model of inflation
• Fast Computation of First-Order Feature-Bispectrum Corrections

Cited by in corpus (24)

• Planck 2018 results. X. Constraints on inflation
• Features and New Physical Scales in Primordial Observables: Theory and Observation
• Oscillations in the stochastic gravitational wave background from sharp features and particle production during inflation
• Turning in the landscape: a new mechanism for generating Primordial Black Holes
• Frame-dependence of higher-order inflationary observables in scalar-tensor theories
• Questions on calculation of primordial power spectrum with large spikes: the resonance model case
• Primordial power spectrum from Planck
• Inflation with moderately sharp features in the speed of sound: GSR and in-in formalism for power spectrum and bispectrum
• Amplification of Primordial Perturbations from the Rise or Fall of the Inflaton
• Primordial Black Holes Arise When The Inflaton Falls
• B-modes and the Nature of Inflation
• Precise measurements of inflationary features with 21 cm observations
• Polyspectra searches for sharp oscillatory features in cosmic microwave sky data
• Untangling features in the primordial spectra
• Inflation in Motion: Unitarity Constraints in Effective Field Theories with Broken Lorentz Symmetry
• Consistency relations for sharp features in the primordial spectra
• Bayesian reconstruction of the inflaton's speed of sound using CMB data
• Nonlinear Excitations in Inflationary Power Spectra
• Bound on Induced Gravitational Waves during Inflation Era
• Perturbative Unitarity of Inflationary Models with Features
• Axion Poltergeist
• Robust predictions for an oscillatory bispectrum in Planck 2015 data from transient reductions in the speed of sound of the inflaton
• Consistency relations for sharp inflationary non-Gaussian features
• Primordial gravitational waves from excited states