How the curvaton scenario, modulated reheating and an inhomogeneous end of inflation are related

Abstract

In this paper we analyse three models of the early universe, for which the respective mechanisms for generating the curvature perturbation are considered disparate. We find that in fact the mechanisms are very similar, and hence explain why they give rise to a large non-gaussianity. We show that the mechanism for generating the primordial curvature perturbation, and hence the observable non-gaussianity, is similar in both the Curvaton and Modulated Reheating models. In both cases the model can be written in terms of an energy transfer between the constituting fluids. We then show that this is also true for the mechanism of generating the curvature perturbation by symmetry breaking the end of inflation. We then relate this to the non-gaussian contribution to the curvature perturbation and find that it is inversely proportional to the efficiency with which the curvature perturbation is transferred between the fluids. For the first time, we generalise models of modulated reheating to allow for a non-linear energy transfer rate.

arXiv comment12 pages, to appear in JCAP

References in corpus (24)

• Non-Gaussian features of primordial fluctuations in single field inflationary models
• Cosmological Constraints from the SDSS Luminous Red Galaxies
• Generating the curvature perturbation without an inflaton
• Adiabatic CMB perturbations in pre-big bang string cosmology
• The primordial density perturbation in the curvaton scenario
• Cosmological perturbations
• A new mechanism for generating density perturbations from inflation
• Non-Gaussianities in models with a varying inflaton decay rate
• Generating the curvature perturbation at the end of inflation
• Optimal limits on f_{NL}^{local} from WMAP 5-year data
• Inflationary models inducing non-Gaussian metric fluctuations
• Cosmic Density Perturbations from Late-Decaying Scalar Condensations
• Multi-brid inflation and non-Gaussianity
• Conditions for large non-Gaussianity in two-field slow-roll inflation
• A numerical study of non-gaussianity in the curvaton scenario
• Modulated fluctuations from hybrid inflation
• Adiabatic and entropy perturbations with interacting fluids and fields
• Non-Gaussianity beyond slow roll in multi-field inflation
• Large non-Gaussianity from multi-brid inflation
• The non-adiabatic pressure in general scalar field systems
• An Estimate of the Primordial Non-Gaussianity Parameter f_NL Using the Needlet Bispectrum from WMAP
• Curvature perturbation from symmetry breaking the end of inflation
• Quintessence with quadratic coupling to dark matter
• Non-gaussianity for a Two Component Hybrid Model of Inflation

Cited by in corpus (10)

• Large-scale Bias and Efficient Generation of Initial Conditions for Non-Local Primordial Non-Gaussianity
• Non-Gaussianity from the hybrid potential
• The next non-Gaussianity frontier: what can a measurement with $\sigma (f_{\mathrm{NL}})\lesssim 1$ tell us about multifield inflation?
• General analytic predictions of two-field inflation and perturbative reheating
• Isocurvature Perturbations and Non-Gaussianity of Gravitationally Produced Nonthermal Dark Matter
• Can Standard Model Higgs Seed the Formation of Structures in Our Universe?
• What Planck does not tell us about inflation
• Thermal Inflation with a Thermal Waterfall Scalar Field Coupled to a Light Spectator Scalar Field
• Non-Gaussianity after many-field reheating
• Non-Gaussianity in D3-brane inflation