The effect of multiple features on the power spectrum in two-field inflation

Abstract

We extend our previous work on the enhancement of the curvature spectrum during inflation to the two-field case. We identify the slow-roll parameter $\eta$ as the quantity that can trigger the rapid growth of perturbations. Its two components, ${\eta }_{\parallel }$ along the background trajectory and ${\eta }_{\perp }$ perpendicular to it, remain small during most of the evolution, apart from short intervals during which they take large, positive or negative, values. The typical reason for the appearance of strong features in ${\eta }_{\parallel }$ is sharp steps or inflection points in the inflaton potential, while ${\eta }_{\perp }$ grows large during sharp turns in field space. We focus on the additive effect of several features leading to the resonant growth of the curvature spectrum. Three or four features in the evolution of $\eta$ are sufficient in order to induce an enhancement of the power spectrum by six or seven orders of magnitude, which can lead to the significant production of primordial black holes and stochastic gravitational waves. A big part of our study focuses on understanding the evolution of the perturbations and the resulting spectra through analytic means. The presence of multiple features in the background evolution points to a more complex inflationary paradigm, which is also more natural in the multi-field case. The critical examination of this possibility is within the reach of experiment.

arXiv comment33 pages, 9 figures

References in corpus (74)

• Planck 2018 results. X. Constraints on inflation
• TianQin: a space-borne gravitational wave detector
• Laser Interferometer Space Antenna
• Science Case for the Einstein Telescope
• Constraints on Primordial Black Holes
• A General Analytic Formula for the Spectral Index of the Density Perturbations produced during Inflation
• Primordial Black Holes - Perspectives in Gravitational Wave Astronomy -
• The NANOGrav 12.5-year Data Set: Search For An Isotropic Stochastic Gravitational-Wave Background
• Nongaussian Isocurvature Perturbations from Inflation
• Gravitational Wave Spectrum Induced by Primordial Scalar Perturbations
• Adiabatic and entropy perturbations from inflation
• The cosmological gravitational wave background from primordial density perturbations
• The international pulsar timing array project: using pulsars as a gravitational wave detector
• Primordial Non-Gaussianities from Inflation Models
• Taiji Program: Gravitational-Wave Sources
• Semianalytic Calculation of Gravitational Wave Spectrum Nonlinearly Induced from Primordial Curvature Perturbations
• Sensitivity curves for searches for gravitational-wave backgrounds
• European Pulsar Timing Array Limits On An Isotropic Stochastic Gravitational-Wave Background
• Primordial black holes from single field models of inflation
• Upper Limits on the Isotropic Gravitational-Wave Background from Advanced LIGO's and Advanced Virgo's Third Observing Run
• Gravitational wave background as a probe of the primordial black hole abundance
• Threshold of primordial black hole formation
• Prospects for Fundamental Physics with LISA
• Features of heavy physics in the CMB power spectrum
• AION: An Atom Interferometer Observatory and Network
• Primordial Black Holes and Slow-Roll Violation
• CMB polarization from secondary vector and tensor modes
• Scalaron from $R^2$-gravity as a Heavy Field
• Metric perturbations in two-field inflation
• Correlated adiabatic and isocurvature perturbations from double inflation
• Features and New Physical Scales in Primordial Observables: Theory and Observation
• Primordial black holes with an accurate QCD equation of state
• The Gelaton Scenario: Equilateral non-Gaussianity from multi-field dynamics
• Primordial Black Holes from $\alpha$-attractors
• Generating PBHs and small-scale GWs in two-field models of inflation
• Isocurvature Perturbations in Multiple Inflationary Models
• Effective theories of single field inflation when heavy fields matter
• Seeding primordial black holes in multifield inflation
• Gravitational Waves Induced by Scalar Perturbations with a Lognormal Peak
• Mass hierarchies and non-decoupling in multi-scalar field dynamics
• On the importance of heavy fields during inflation
• Heavy fields, reduced speeds of sound and decoupling during inflation
• Primordial black hole formation in the matter-dominated phase of the Universe
• Oscillations in the stochastic gravitational wave background from sharp features and particle production during inflation
• Strongly Coupled Perturbations in Two-Field Inflationary Models
• Curvature Perturbation Spectrum in Two-field Inflation with a Turning Trajectory
• Hyperinflation
• Effective Field Theory and Decoupling in Multi-field Inflation: An Illustrative Case Study
• Influence of heavy modes on perturbations in multiple field inflation
• Black hole formation from a general quadratic action for inflationary primordial fluctuations
• Correlating features in the primordial spectra
• Probing Primordial Features with the Stochastic Gravitational Wave Background
• On the slope of curvature power spectrum in non-attractor inflation
• An analytic approach to non-slow-roll inflation
• Amplification of Primordial Perturbations from the Rise or Fall of the Inflaton
• Scaling attractors in multi-field inflation
• Density Perturbations in Multifield Inflationary Models
• Revisiting small-scale fluctuations in $\alpha$-attractor models of inflation
• Hyper non-Gaussianities in inflation with strongly non-geodesic motion
• Generation of gravitational waves during early structure formation between cosmic inflation and reheating
• The rapid-turn inflationary attractor
• Primordial black holes from modified supergravity
• Scratches from the Past: Inflationary Archaeology through Features in the Power Spectrum of Primordial Fluctuations
• Features of the inflaton potential and the power spectrum of cosmological perturbations
• Spectrum oscillations from features in the potential of single-field inflation
• New constraints on multi-field inflation with nonminimal coupling
• Decoupling Survives Inflation: A Critical Look at Effective Field Theory Violations During Inflation
• Gravitational Waves from Density Perturbations in an Early Matter Domination Era
• Exploring the Spectral Shape of Gravitational Waves Induced by Primordial Scalar Perturbations and Connection with the Primordial Black Hole Scenarios
• Shift-Symmetric Orbital Inflation: single field or multi-field?
• Gravitational Waves and Primordial Black Holes from Supersymmetric Hybrid Inflation
• Density fluctuations in Brans-Dicke inflation
• Rollercoaster Cosmology
• The effects of a fast-turning trajectory in multiple-field inflation

Cited by in corpus (10)

• Hybrid $\alpha$-attractors, primordial black holes and gravitational wave backgrounds
• Primordial black holes and gravitational waves from nonminimally coupled supergravity inflation
• The Inflaton that Could : Primordial Black Holes and Second Order Gravitational Waves from Tachyonic Instability induced in Higgs-$R^2$ Inflation
• Sharp turns in axion monodromy: primordial black holes and gravitational waves
• Primordial black holes from an inflationary potential valley
• Exploring Critical Overdensity Thresholds in Inflationary Models of Primordial Black Holes Formation
• Primordial Black Hole Formation from Power Spectrum with Finite-width
• Enhanced power spectra from multi-field inflation
• Log-periodic gravitational-wave background beyond Einstein gravity
• Potential Surge Preheating: enhanced resonance from potential features