Effective Field Theory of Multi-Field Inflation a la Weinberg

Abstract

We employ the effective field theory approach for multi-field inflation which is a generalization of Weinberg's work. In this method the first correction terms in addition to standard terms in the Lagrangian have been considered. These terms contain up to the fourth derivative of the fields including the scalar field and the metric. The results show the possible shapes of the interaction terms resulting eventually in non-Gaussianity in a general formalism. In addition generally the speed of sound is different but almost unity. Since in this method the adiabatic mode is not discriminated initially so we define the adiabatic as well as entropy modes for a specific two-field model. It has been shown that the non-Gaussianity of the adiabatic mode and the entropy mode are correlated in shape and amplitude. It is shown that even for speed close to unity large non-Gaussianities are possible in multi-field case. The amount of the non-Gaussianity depends on the curvature of the classical path in the phase-space in the Hubble unit such that it is large for the large curvature. In addition it is emphasized that the time derivative of adiabatic and entropy perturbations do not transform due to the shift symmetry as well as the original perturbations. Though two specific combinations of them are invariant under such a symmetry and these combinations should be employed to construct an effective field theory of multi-field inflation.

16 pages, comments are welcome

References in corpus (13)

• The Effective Field Theory of Inflation
• Primordial Non-Gaussianities from Inflation Models
• Effective Field Theory for Inflation
• Starting the Universe: Stable Violation of the Null Energy Condition and Non-standard Cosmologies
• Galileon inflation
• On the importance of heavy fields during inflation
• Strongly Coupled Perturbations in Two-Field Inflationary Models
• Effective Field Theory and Decoupling in Multi-field Inflation: An Illustrative Case Study
• Large non-Gaussianities in the Effective Field Theory Approach to Single-Field Inflation: the Trispectrum
• A Field Range Bound for General Single-Field Inflation
• Nonlinear perturbations of cosmological scalar fields with non-standard kinetic terms
• Separable and non-separable multi-field inflation and large non-Gaussianity
• Testing Two-Field Inflation

Cited by in corpus (15)

• Dark Energy or Modified Gravity? An Effective Field Theory Approach
• Signatures of Supersymmetry from the Early Universe
• Inflation Physics from the Cosmic Microwave Background and Large Scale Structure
• Quantum loop effects on the power spectrum and constraints on primordial black holes
• Effective field theory of weakly coupled inflationary models
• Can Effective Field Theory of inflation generate large tensor-to-scalar ratio within Randall Sundrum single braneworld?
• Resonant Signatures of Heavy Scalar Fields in the Cosmic Microwave Background
• Cosmological Implications of the Effective Field Theory of Cosmic Acceleration
• Localized Features in Non-Gaussianity from Heavy Physics
• Large fluctuations and Primordial Black Holes
• Local non-Gaussianity from rapidly varying sound speeds
• On degenerate models of cosmic inflation
• Consistency relations in multi-field inflation
• The Trispectrum in the Effective Theory of Inflation with Galilean symmetry
• Loop-Induced Stochastic Bias at Small Wavevectors