Cosmological density perturbations from perturbed couplings

Abstract

The density perturbations generated when the inflaton decay rate is perturbed by a light scalar field $\chi$ are studied. By explicitly solving the perturbation equations for the system of two scalar fields and radiation, we show that even in low energy-scale inflation nearly scale-invariant spectra of scalar perturbations with an amplitude set by observations are obtained through the conversion of $\chi$ fluctuations into adiabatic density perturbations. We demonstrate that the spectra depend on the average decay rate of the inflaton & on the inflaton fluctuations. We then apply this new mechanism to string cosmologies & generalized Einstein theories and discuss the conditions under which scale-invariant spectra are possible.

arXiv comment5 pages, 2 eps figures, references are added. Accepted for publication in Physical Review D

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Cited by in corpus (24)

• Inflation Dynamics and Reheating
• Quantum corrections to slow roll inflation and new scaling of superhorizon fluctuations
• Models of inflation liberated by the curvaton hypothesis
• Can the curvaton paradigm accommodate a low inflation scale?
• Particle decay during inflation: self-decay of inflaton quantum fluctuations during slow roll
• Cosmological perturbations from varying masses and couplings
• Particle decay in inflationary cosmology
• WMAP, neutrino degeneracy and non-Gaussianity constraints on isocurvature perturbations in the curvaton model of inflation
• Modulated Perturbations from Instant Preheating after new Ekpyrosis
• Cosmological perturbations from inhomogeneous preheating and multi-field trapping
• Fluctuating annihilation cross sections and the generation of density perturbations
• NO Curvatons or Hybrid Quintessential Inflation
• Cosmological perturbations for imperfect fluids
• Generating curvature perturbations with or without MSSM flat directions
• Inhomogeneous reheating scenario with low scale inflation and/or MSSM flat directions
• Reheating in tachyonic inflationary models: Effects on the large scale curvature perturbations
• Hybrid Curvatons from Broken Symmetry
• The inflationary origin of the Cold Spot anomaly
• Light Scalars and the Generation of Density Perturbations During Preheating or Inflaton Decay
• Scalar Perturbation Spectra in an Emergent Cosmological Island
• Generating cosmological perturbations with mass variations
• Cosmological Perturbations During Radion Stabilization
• On Primordial Perturbations of Test Scalar Fields
• Hidden in the background: a local approach to CMB anomalies