Combined local and equilateral non-Gaussianities from multifield DBI inflation

Abstract

We study multifield aspects of Dirac-Born-Infeld (DBI) inflation. More specifically, we consider an inflationary phase driven by the radial motion of a D-brane in a conical throat and determine how the D-brane fluctuations in the angular directions can be converted into curvature perturbations when the tachyonic instability arises at the end of inflation. The simultaneous presence of multiple fields and non-standard kinetic terms gives both local and equilateral shapes for non-Gaussianities in the bispectrum. We also study the trispectrum, pointing out that it acquires a particular momentum dependent component whose amplitude is given by $f_{NL}^{loc}{f}_{NL}^{eq}$. We show that this relation is valid in every multifield DBI model, in particular for any brane trajectory, and thus constitutes an interesting observational signature of such scenarios.

38 pages, 11 figures. Typos corrected; references added. This version matches the one in press by JCAP

References in corpus (53)

• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• The Effective Field Theory of Inflation
• Observational Signatures and Non-Gaussianities of General Single Field Inflation
• Non-Gaussianities in Single Field Inflation and their Optimal Limits from the WMAP 5-year Data
• Effects of Scale-Dependent Non-Gaussianity on Cosmological Structures
• Primordial perturbations and non-Gaussianities in DBI and general multi-field inflation
• Perturbations in generalized multi-field inflation
• Primordial trispectrum from inflation
• A Microscopic Limit on Gravitational Waves from D-brane Inflation
• A Delicate Universe
• Angular Trispectrum of CMB Temperature Anisotropy from Primordial Non-Gaussianity with the Full Radiation Transfer Function
• The Inflationary Trispectrum for Models with Large Non-Gaussianities
• Probing String Theory with Modulated Cosmological Fluctuations
• Primordial fluctuations and non-Gaussianities in multi-field DBI inflation
• Multi-brid inflation and non-Gaussianity
• Primordial non-Gaussianity, scale-dependent bias, and the bispectrum of galaxies
• Constraining Running Non-Gaussianity
• Non-Gaussianity beyond slow roll in multi-field inflation
• Phenomenology of D-Brane Inflation with General Speed of Sound
• Large non-Gaussianity from multi-brid inflation
• Inflation with multiple sound speeds: a model of multiple DBI type actions and non-Gaussianities
• Comparing Infrared Dirac-Born-Infeld Brane Inflation to Observations
• Nongaussianity from Tachyonic Preheating in Hybrid Inflation
• The curvature perturbation in a box
• On the full trispectrum in single field DBI-inflation
• Primordial Non-Gaussianities of General Multiple Field Inflation
• On the Issue of the ζSeries Convergence and Loop Corrections in the Generation of Observable Primordial Non-Gaussianity in Slow-Roll Inflation. Part I: the Bispectrum
• DBI Inflation in the Tip Region of a Warped Throat
• Simple Bounds from the Perturbative Regime of Inflation
• A geometric description of the non-Gaussianity generated at the end of multi-field inflation
• Diagrammatic approach to non-Gaussianity from inflation
• Curvature perturbation from symmetry breaking the end of inflation
• Gravitational Wave Constraints on DBI Inflation
• Generating the Curvature Perturbation at the End of Inflation in String Theory
• Multifield Cosmological Perturbations at Third Order and the Ekpyrotic Trispectrum
• Lorentz boost and non-Gaussianity in multi-field DBI-inflation
• The trispectrum of 21-cm background anisotropies as a probe of primordial non-Gaussianity
• Primordial Trispectrum from Entropy Perturbations in Multifield DBI Model
• N-flation from multiple DBI type actions
• Nonlinear perturbations of cosmological scalar fields with non-standard kinetic terms
• Is Brane Inflation Eternal?
• Primordial Non-Gaussianities from the Trispectra in Multiple Field Inflationary Models
• Higher order contributions to the primordial non-gaussianity
• The Trispectrum in the Multi-brid Inflation
• D3-brane Vacua in Stabilized Compactifications
• Cosmological constraints on string scale and coupling arising from tachyonic instability
• Non-Gaussianities in extended D-term inflation
• Systematics of multi-field effects at the end of warped brane inflation
• Inflation, quantum fluctuations and cosmological perturbations
• Loop Corrections to Cosmological Perturbations in Multi-field Inflationary Models
• Tachyon Mediated Non-Gaussianity
• Brane Inflation and the Overshoot Problem

Cited by in corpus (41)

• Cosmology and Fundamental Physics with the Euclid Satellite
• Cosmology and fundamental physics with the Euclid satellite
• Primordial Non-Gaussianities from Inflation Models
• Quasi-Single Field Inflation and Non-Gaussianities
• Primordial non-Gaussianity and Bispectrum Measurements in the Cosmic Microwave Background and Large-Scale Structure
• Primordial non-Gaussianity from the DBI Galileons
• Strongly Coupled Perturbations in Two-Field Inflationary Models
• General CMB and Primordial Trispectrum Estimation
• On Classification of Models of Large Local-Type Non-Gaussianity
• Primordial fluctuations and non-Gaussianities from multifield DBI Galileon inflation
• A note on the equivalence of a barotropic perfect fluid with a K-essence scalar field
• Large and strong scale dependent bispectrum in single field inflation from a sharp feature in the mass
• Unwinding Inflation
• Primordial non-Gaussianities after Planck 2015: an introductory review
• Non-Gaussianity Generated by the Entropic Mechanism in Bouncing Cosmologies Made Simple
• Non-Gaussianity in single field models without slow-roll
• Multi-field G-inflation
• Strong scale dependent bispectrum in the Starobinsky model of inflation
• Cosmological Dynamics of a Dirac-Born-Infeld field
• Transport equations for the inflationary trispectrum
• Trispectrum from Ghost Inflation
• Non-Gaussianities of Single Field Inflation with Non-minimal Coupling
• General formula for the running of local fNL
• Inflationary predictions in scalar-tensor DBI inflation
• On Cross-correlations between Curvature and Isocurvature Perturbations during Inflation
• The trispectrum in ghost inflation
• Trispectrum estimation in various models of equilateral type non-Gaussianity
• Enhanced Inflation in the Dirac-Born-Infeld framework
• Local non-Gaussianity from rapidly varying sound speeds
• DBI Galileon in the Effective Field Theory of Inflation: Orthogonal non-Gaussianities and constraints from the Trispectrum
• Fields Annihilation and Particles Creation in DBI inflation
• δN versus covariant perturbative approach to non-Gaussianity outside the horizon in multifield inflation
• The probability distribution for non-Gaussianity estimators constructed from the CMB trispectrum
• Quadra-Spectrum and Quint-Spectrum from Inflation and Curvaton Models
• Non-Gaussianities in multi-field DBI inflation with a waterfall phase transition
• Non-Gaussian Shape Discrimination with Spectroscopic Galaxy Surveys
• Non-Gaussianity in rapid-turn multi-field inflation
• Non-Gaussianities in DBI inflation with angular motion
• Measuring CMB non-Gaussianity as a probe of Inflation and Cosmic Strings
• Cosmological Perturbations in Inflationary Models with Anisotropic Space-Time Scaling in Lifshitz Background
• Cosmological signatures of brane inflation