Curvature and Entropy Perturbations in Generalized Gravity

Abstract

We investigate the cosmological perturbations in generalized gravity, where the Ricci scalar and a scalar field are non-minimally coupled via an arbitrary function. In the Friedmann-Lemaitre-Robertson-Walker background, by studying the linear perturbation theory, we separate the scalar type perturbations into the curvature perturbation and the entropy perturbation, whose evolution equations are derived. Then we apply this framework to inflation. We consider the generalized slow-roll conditions and the quantization initial condition. Under these conditions, two special examples are studied analytically. One example is the case with no entropy perturbation. The other example is a model with the entropy perturbation large initially but decaying significantly after crossing the horizon.

30 pages, 4 figures, references added

References in corpus (26)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Introduction to Modified Gravity and Gravitational Alternative for Dark Energy
• Generating the curvature perturbation without an inflaton
• The primordial density perturbation in the curvaton scenario
• The Fifth Data Release of the Sloan Digital Sky Survey
• Adiabatic and entropy perturbations from inflation
• Extended Gravity Theories and the Einstein-Hilbert Action
• Classical evolution and quantum generation in generalized gravity theories including string corrections and tachyon: Unified analyses
• Metric perturbations in two-field inflation
• Scalar perturbations during multiple-field slow-roll inflation
• Correlated adiabatic and isocurvature perturbations from double inflation
• An Observational Test of Two-field Inflation
• Adiabatic and Isocurvature Perturbations for Multifield Generalized Einstein Models
• Curvature and isocurvature perturbations from two-field inflation in a slow-roll expansion
• Matter density perturbations in modified gravity models with arbitrary coupling between matter and geometry
• Evolution of Structures in Generalized Gravity Theories
• Curvaton Dynamics and the Non-Linearity Parameters in Curvaton Model
• Large Non-Gaussianity Implication for Curvaton Scenario
• Quantum fluctuations of Cosmological Perturbations in Generalized Gravity
• Slow-roll Inflation for Generalized Two-Field Lagrangians
• Newton's constant in f(R,R_{μν}R^{μν},\Box R) theories of gravity and constraints from BBN
• Gravitational Wave Spectrums from Pole-like Inflations based on Generalized Gravity Theories
• N-vaton
• "Phantom" Inflation in Warped Compactification
• Inflation with High Derivative Couplings
• Nonminimal Inflation and the Running Spectral Index

Cited by in corpus (13)

• f(R) theories
• Cosmological reconstruction of realistic modified F(R) gravities
• Primordial Trispectrum from Entropy Perturbations in Multifield DBI Model
• Primordial Non-Gaussianities from the Trispectra in Multiple Field Inflationary Models
• The Trispectrum in the Multi-brid Inflation
• On higher derivative corrections to the $R+R^2$ inflationary model
• Note on Non-Gaussianities in Two-field Inflation
• Anisotropic singularities in modified gravity models
• On Cross-correlations between Curvature and Isocurvature Perturbations during Inflation
• Evolution of curvature perturbation in generalized gravity theories
• Coupling structure of multi-field primordial perturbations
• On primordial trispectrum from exchanging scalar modes in general multiple field inflationary models
• 1/R Correction to Gravity in the Early Universe