Must Cosmological Perturbations Remain Non-Adiabatic After Multi-Field Inflation?

Abstract

Even if non-adiabatic perturbations are generated in multi-field inflation, the perturbations will become adiabatic if the universe after inflation enters an era of local thermal equilibrium, with no non-zero conserved quantities, and will remain adiabatic as long as the wavelength is outside the horizon, even when local thermal equilibrium no longer applies. Small initial non-adiabatic perturbations associated with imperfect local thermal equilibrium remain small when baryons are created from out-of-equilibrium decay of massive particles, or when dark matter particles go out of local thermal equilibrium.

arXiv comment12 pages, typographical errors corrected, acknowledgment added. Article accepted for publication in Physical Review D

References in corpus (12)

• Generating the curvature perturbation without an inflaton
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for Inflation
• A new approach to the evolution of cosmological perturbations on large scales
• Effects of Cosmological Moduli Fields on Cosmic Microwave Background
• The primordial density perturbation in the curvaton scenario
• Signatures of Relativistic Neutrinos in CMB Anisotropy and Matter Clustering
• Adiabatic Modes in Cosmology
• Large-scale curvature and entropy perturbations for multiple interacting fluids
• Isocurvature Perturbations in Multiple Inflationary Models
• Bounds on isocurvature perturbations from CMB and LSS data
• The CDM isocurvature perturbation in the curvaton scenario
• CMB Anisotropy from Baryogenesis by a Scalar Field

Cited by in corpus (68)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Planck 2013 results. XXII. Constraints on inflation
• Inflation Dynamics and Reheating
• Cosmology and Fundamental Physics with the Euclid Satellite
• Cosmology and fundamental physics with the Euclid satellite
• The First Three Seconds: a Review of Possible Expansion Histories of the Early Universe
• Cosmological Moduli and the Post-Inflationary Universe: A Critical Review
• Non-linear isocurvature perturbations and non-Gaussianities
• Exploring Cosmic Origins with CORE: Inflation
• Multiple field inflation
• Isocurvature bounds on axions revisited
• Evolution of fNL to the adiabatic limit
• A Scale-Dependent Power Asymmetry from Isocurvature Perturbations
• Correlated isocurvature perturbations from mixed inflaton-curvaton decay
• Bounds on CDM and neutrino isocurvature perturbations from CMB and LSS data
• The exact numerical treatment of inflationary models
• Squeezing the window on isocurvature modes with the Lyman-alpha forest
• Axion dark matter from Higgs inflation with an intermediate $H_{\ast }$
• Growth of Dark Matter Perturbations during Kination
• Inflation, the Hubble Tension and Early Dark Energy: an alternative overview
• Non-Gaussianities in Multifield Inflation: Superhorizon Evolution, Adiabaticity, and the Fate of fnl
• Spotting deviations from R^2 inflation
• Perturbative Reheating After Multiple-Field Inflation: The Impact on Primordial Observables
• Primordial Perturbations in Einstein-Aether and BPSH Theories
• Inflation with an extra light scalar field after Planck
• Constant roll inflation in multifield models
• Converting entropy to curvature perturbations after a cosmic bounce
• Power Spectra Based Planck Constraints on Compensated Isocurvature, and Forecasts for LiteBIRD and CORE Space Missions
• Constraining Curvatonic Reheating
• The next non-Gaussianity frontier: what can a measurement with $\sigma (f_{\mathrm{NL}})\lesssim 1$ tell us about multifield inflation?
• High-Scale Axions without Isocurvature from Inflationary Dynamics
• Large trispectrum in two-field slow-roll inflation
• Constraining SUSY with Heavy Scalars -- using the CMB
• Seven Lessons from Manyfield Inflation in Random Potentials
• Measuring the duration of inflation with the curvaton
• Neutralino Dark Matter and the Curvaton
• Adiabaticity and the Fate of Non-Gaussianities: The Trispectrum and Beyond
• Inflation in Multi-field Modified DBM Potentials
• Tracking the Multifield Dynamics with Cosmological Data: A Monte Carlo approach
• Constraints on moduli cosmology from the production of dark matter and baryon isocurvature fluctuations
• Effect of reheating on predictions following multiple-field inflation
• Probing Compensated Isocurvature with the 21-cm Signal during Cosmic Dawn
• Exploring ALPs beyond the canonical
• Entropy Production in Affine Inflation
• Exploring Two-Field Inflation in the Wess-Zumino Model
• A Bump in the Blue Axion Isocurvature Spectrum
• On the perturbation theory in spatially closed background
• Induced gravitational waves and baryon asymmetry fluctuations from primordial black hole formation
• Rotating baryonic dark halos
• BBN constraints on dark radiation isocurvature
• Curvaton Decay into Baryons, anti-Baryons and Radiation
• Improving Constraints on Inflation with CMB Delensing
• Impact of freeze-in on dark matter isocurvature
• 1/R Correction to Gravity in the Early Universe
• The two-field regime of natural inflation
• Constraints on variations in inflaton decay rate from modulated preheating
• Dark Matter from freeze-in and its inhomogeneities
• Isocurvature modes and non-Gaussianity in affine inflation
• QCD axion dark matter and the cosmic dipole problem
• Optimal bispectrum constraints on single-field models of inflation
• Warm Ekpyrosis
• Possible origin of CMB temperature fluctuations: Vacuum fluctuations of Kaluza-Klein and string states during inflationary era
• Non-linear effects in early Universe cosmology
• Infrared Sensitivity of Cosmological Probes in Horndeski Theory
• Generalized neutrino isocurvature
• Testing Inflationary Cosmology
• Leptogenesis with perturbations in type-II and type-III seesaw models
• Non-Gaussianity in D3-brane inflation