On the importance of heavy fields during inflation

Abstract

We study the dynamics of two-field models of inflation characterized by a hierarchy of masses between curvature and isocurvature modes. When the hierarchy is large, a low energy effective field theory (EFT) exists in which only curvature modes participate in the dynamics of perturbations. In this EFT heavy fields continue to have a significant role in the low energy dynamics, as their interaction with curvature modes reduces their speed of sound whenever the multi-field trajectory is subject to a sharp turn in target space. Here we analyze under which general conditions this EFT remains a reliable description for the linear evolution of curvature modes. We find that the main condition consists on demanding that the rate of change of the turn's angular velocity stays suppressed with respect to the masses of heavy modes. This adiabaticity condition allows the EFT to accurately describe a large variety of situations in which the multi-field trajectory is subject to sharp turns. To test this, we analyze several models with turns and show that, indeed, the power spectra obtained for both the original two-field theory and its single-field EFT are identical when the adiabaticity condition is satisfied. In particular, when turns are sharp and sudden, they are found to generate large features in the power spectrum, accurately reproduced by the EFT.

34 pages, 10 figures. v2: improved discussion on the validity of the EFT, added references. v3: minor changes, version as in JCAP

References in corpus (28)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Cosmological Constraints from the SDSS Luminous Red Galaxies
• The Effective Field Theory of Inflation
• Observational Signatures and Non-Gaussianities of General Single Field Inflation
• Monodromy in the CMB: Gravity Waves and String Inflation
• Effective Field Theory for Inflation
• Perturbations in generalized multi-field inflation
• Curvature and isocurvature perturbations in two-field inflation
• Mass hierarchies and non-decoupling in multi-scalar field dynamics
• Clustering of Sloan Digital Sky Survey III Photometric Luminous Galaxies: The Measurement, Systematics and Cosmological Implications
• Strongly Coupled Perturbations in Two-Field Inflationary Models
• Axion Inflation in Type II String Theory
• Acoustic scale from the angular power spectra of SDSS-III DR8 photometric luminous galaxies
• Effective Field Theory and Decoupling in Multi-field Inflation: An Illustrative Case Study
• Effects of particle production during inflation
• Energy Transfer in Multi Field Inflation and Cosmological Perturbations
• Accidental Inflation in String Theory
• On Features and Nongaussianity from Inflationary Particle Production
• Power Spectrum and Signatures for Cascade Inflation
• WMAP 7 Constraints on Oscillations in the Primordial Power Spectrum
• The Importance of Slow-roll Corrections During Multi-field Inflation
• Constructing de Sitter vacua in no-scale string models without uplifting
• Sudden variations in the speed of sound during inflation: features in the power spectrum and bispectrum
• Globally and locally supersymmetric effective theories for light fields
• Evolution of the curvature perturbation during and after multi-field inflation
• On the Effective Description of Large Volume Compactifications
• Testing Two-Field Inflation
• Bigravitational inflation

Cited by in corpus (116)

• Scalaron from $R^2$-gravity as a Heavy Field
• Effective field theory approach to quasi-single field inflation and effects of heavy fields
• Features and New Physical Scales in Primordial Observables: Theory and Observation
• Quasi-Single Field Inflation with Large Mass
• Effective theories of single field inflation when heavy fields matter
• Seeding primordial black holes in multifield inflation
• Heavy fields, reduced speeds of sound and decoupling during inflation
• Inflation, Cosmic Perturbations and Non-Gaussianities
• Signs of Analyticity in Single-Field Inflation
• Oscillations in the stochastic gravitational wave background from sharp features and particle production during inflation
• Teasing bits of information out of the CMB energy spectrum
• Curvature Perturbation Spectrum in Two-field Inflation with a Turning Trajectory
• Influence of heavy modes on perturbations in multiple field inflation
• Distinguishing different scenarios of early energy release with spectral distortions of the cosmic microwave background
• Equilateral non-Gaussianity from heavy fields
• An effective field theory during inflation: reduced density matrix and its quantum master equation
• The Science of the Einstein Telescope
• Correlating features in the primordial spectra
• Density profiles of ultracompact minihalos: Implications for constraining the primordial power spectrum
• Inflating in a Trough: Single-Field Effective Theory from Multiple-Field Curved Valleys
• Primordial fluctuations and non-Gaussianities in sidetracked inflation
• Are ultracompact minihalos really ultracompact?
• A Statistical Approach to Multifield Inflation: Many-field Perturbations Beyond Slow Roll
• A new probe of the small-scale primordial power spectrum: astrometric microlensing by ultracompact minihalos
• Inflation with moderately sharp features in the speed of sound: GSR and in-in formalism for power spectrum and bispectrum
• On the time evolution of cosmological correlators
• An effective field theory during inflation II: stochastic dynamics and power spectrum suppression
• Effective field theory of weakly coupled inflationary models
• Planck-Suppressed Operators
• Localized correlated features in the CMB power spectrum and primordial bispectrum from a transient reduction in the speed of sound
• The rapid-turn inflationary attractor
• Multi-field inflation and cosmological perturbations
• B-modes and the Nature of Inflation
• Cumulative effects in inflation with ultra-light entropy modes
• Revisiting non-Gaussianity in multifield inflation with curved field space
• Landscape tomography through primordial non-Gaussianity
• Modulated Reheating and Large Non-Gaussianity in String Cosmology
• Breaking discrete symmetries in the effective field theory of inflation
• Oscillatory features in the curvature power spectrum after a sudden turn of the inflationary trajectory
• High Energy Physics Signatures from Inflation and Conformal Symmetry of de Sitter
• Large power spectrum and primordial black holes in the effective theory of inflation
• Large non-Gaussian Halo Bias from Single Field Inflation
• Untangling features in the primordial spectra
• Cosmic inflation in a landscape of heavy-fields
• On Primordial Black Holes from Rapid Turns in Two-field Models
• Multifield inflation beyond $N_{\mathrm{field}}=2$: non-Gaussianities and single-field effective theory
• Correlating correlation functions of primordial perturbations
• Fat Inflatons, Large Turns and the $\eta$-problem
• Probing Two-Field Open Inflation by Resonant Signals in Correlation Functions
• Primordial spectra from sudden turning trajectory
• Resonant Signatures of Heavy Scalar Fields in the Cosmic Microwave Background
• On the Unlikeliness of Multi-Field Inflation: Bounded Random Potentials and our Vacuum
• Mild Non-Gaussianities under Perturbative Control from Rapid-Turn Inflation Models
• Constraints on inflation with LSS surveys: features in the primordial power spectrum
• Searching for primordial localized features with CMB and LSS spectra
• Tidal evolution of dark matter annihilation rates in subhalos
• Evolution of dark matter microhalos through stellar encounters
• On the viability of m**2 phi**2 and natural inflation
• The Inflaton that Could : Primordial Black Holes and Second Order Gravitational Waves from Tachyonic Instability induced in Higgs-$R^2$ Inflation
• On the integration of fields and quanta in time dependent backgrounds
• Localized Features in Non-Gaussianity from Heavy Physics
• The effects of a fast-turning trajectory in multiple-field inflation
• Consistency relations for sharp features in the primordial spectra
• Sharp turns in axion monodromy: primordial black holes and gravitational waves
• Lensing anomaly and oscillations in the primordial power spectrum
• Decoherence out of fire: Purity loss in expanding and contracting universes
• Bayesian reconstruction of the inflaton's speed of sound using CMB data
• Back to the features: assessing the discriminating power of future CMB missions on inflationary models
• Higher derivatives and power spectrum in effective single field inflation
• Effect of transitions in the Planck mass during inflation on primordial power spectra
• Correlating CMB Spectral Distortions with Temperature: what do we learn on Inflation?
• Cosmology of Axions and Moduli: A Dynamical Systems Approach
• The effect of multiple features on the power spectrum in two-field inflation
• Effective Field Theory of Multi-Field Inflation a la Weinberg
• Robust predictions for an oscillatory bispectrum in Planck 2015 data from transient reductions in the speed of sound of the inflaton
• On degenerate models of cosmic inflation
• Dark Energy from Inspiraling in Field Space
• Non-Gaussianities in models of inflation with large and negative entropic masses
• Combined features in the primordial spectra induced by a sudden turn in two-field DBI inflation
• Towards general patterns of features in multi-field inflation
• Sudden braking and turning with a two-field potential bump: primordial black hole formation
• Dynamical consistency conditions for rapid turn inflation
• Power-law modulation of the scalar power spectrum from a heavy field with a monomial potential
• Consistency relations in multi-field inflation
• A Smooth Landscape: Ending Saddle Point Inflation Requires Features to be Shallow
• Non-Gaussianities in a two-field generalization of Natural Inflation
• (Slow-)Twisting inflationary attractors
• A General Framework of Automorphic Inflation
• Dark Matter from Entropy Perturbations in Curved Field Space
• Observational Constraints on Two-field Warm Inflation
• Revisiting isocurvature bounds in models unifying the axion with the inflaton
• Coupling structure of multi-field primordial perturbations
• Reconstructing the EFT of Inflation from Cosmological Data
• (Super)Universal Attractors and the de Sitter Vacua in String Landscape
• A Universal Bound on Excitations of Heavy Fields during Inflation
• Adiabatic and isocurvature perturbations in extended theories with kinetic couplings
• Radiative Corrections from Heavy Fast-Roll Fields during Inflation
• Multi-field Cuscuton Cosmology
• Multi-field Mimetic Gravity
• Entanglement masquerading in the CMB
• Two-field Warm Inflation and Its Scalar Perturbations on Large Scales
• Model-independent approach to effective sound speed in multi-field inflation
• Covariant evolution of perturbations during reheating in two-field inflation
• Primordial Black Hole Generation in a Two-field Inflationary Model
• Flattened Axion Monodromy Beyond Two Derivatives
• B-modes and the sound speed of primordial fluctuations
• Light field integration in SUGRA theories
• On the Consistency of Rapid-Turn Inflation
• Loops in inflation with strongly non-geodesic motion
• The UV Sensitivity of Axion Monodromy Inflation
• Revisiting the oscillations in the CMB angular power spectra at $\ell \sim 120$ in the Planck2015 data
• Cosmological perturbations in the spatially covariant gravity with a dynamical lapse function
• Mimicking two field inflationary features with a single field
• On the importance of heavy fields in pseudo-scalar inflation
• Investigating the Constraints on Primordial Features with Future Cosmic Microwave Background and Galaxy Surveys
• Disappearing Inflaton Potential via Heavy Field Dynamics