Primordial Non-Gaussianities of General Multiple Field Inflation

Abstract

We perform a general study of the primordial scalar non-Gaussianities in multi-field inflationary models in Einstein gravity. We consider models governed by a Lagrangian which is a general function of the scalar fields and their first spacetime derivatives. We use $\delta N$ formalism to relate scalar fields and curvature perturbations. We calculate the explicit cubic order perturbation action and the three-point function of curvature perturbation evaluated at horizon-crossing. Under reasonable assumptions, in the limit of small slow-varying parameters and a sound speed $c_s$ close to one, we find that the non-Gaussianity is completely determined by these slow-varying parameters and some other parameters determined by the structure of the inflationary models. Our work generalizes previous results, and would be useful to study non-Gaussianity in multi-field inflationary models that will be constructed in the future.

26 pages, no figure; v2, minor revision; v3 minor misprints corrected; v4 minor misprints corrected

References in corpus (19)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• String Cosmology: A Review
• Perturbations in generalized multi-field inflation
• Primordial trispectrum from inflation
• Non-Gaussianity, Spectral Index and Tensor Modes in Mixed Inflaton and Curvaton Models
• Non-gaussianity from the second-order cosmological perturbation
• Non-Gaussianity from Preheating
• Non-gaussianity from the trispectrum in general single field inflation
• Non-Gaussianity from Instant and Tachyonic Preheating
• Multifield DBI Inflation and Non-Gaussianities
• A high-significance detection of non-Gaussianity in the WMAP 5-year data using directional spherical wavelets
• Large Non-Gaussianity Implication for Curvaton Scenario
• Seed perturbations for primordial magnetic fields from MSSM flat directions
• Non-gaussianity of inflationary field perturbations from the field equation
• Primordial non-Gaussianity from two curvaton decays
• Non-Gaussianity in braneworld and tachyon inflation
• Cosmological constraints on string scale and coupling arising from tachyonic instability
• Non-Gaussianity in three fluid curvaton model
• Revisiting non-Gaussianity of multiple-field inflation from the field equation

Cited by in corpus (17)

• Primordial perturbations and non-Gaussianities in DBI and general multi-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
• Curvaton Dynamics and the Non-Linearity Parameters in Curvaton Model
• On the full quantum trispectrum in multi-field DBI inflation
• Lorentz boost and non-Gaussianity in multi-field DBI-inflation
• Primordial Trispectrum from Entropy Perturbations in Multifield DBI Model
• Nonlinear perturbations of cosmological scalar fields with non-standard kinetic terms
• Constraints on Kinetically Modified Inflation from WMAP5
• The Trispectrum in the Multi-brid Inflation
• $\alpha$-vacuum and inflationary bispectrum
• N-vaton
• Multi-field Inflation with a Random Potential
• Anisotropic singularities in modified gravity models
• Spectral Index in Curvaton Scenario
• Inflation on an Open Racetrack
• Reconstruction of the isocurvaton scenario
• On the four-dimensional effective theories in brane-worlds