Curvature perturbation from velocity modulation

Abstract

We propose a new variant model of the modulated reheating. If particles have large scale fluctuations on their velocities, or equivalently their Lorentz factors, the decay rate also fluctuates and the curvature perturbation is induced via their decay processes in analogy with modulated reheating. For example, if they are produced nonthermally by the decay of another field with its mass fluctuating on large scales, such a situation is realized. We explicitly calculate the resulting curvature perturbation and non-linearity parameters and show that the effect of velocity-modulation is not negligible if the particles are semi-relativistic at the decay.

16 pages, 2 figures; minor correction; to appear in Phys.Rev.D

References in corpus (9)

• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Non-Gaussianity in the modulated reheating scenario
• Primordial Curvature Fluctuation and Its Non-Gaussianity in Models with Modulated Reheating
• Cosmological Fluctuations from Infra-Red Cascading During Inflation
• Preheating and the non-gaussianity of the curvature perturbation
• Primordial perturbations and non-Gaussianities from modulated trapping
• Cosmological perturbations from inhomogeneous preheating and multi-field trapping
• Cosmological perturbations from an inhomogeneous phase transition
• Generating the primordial curvature perturbations in preheating

Cited by in corpus (3)

• The next non-Gaussianity frontier: what can a measurement with $\sigma (f_{\mathrm{NL}})\lesssim 1$ tell us about multifield inflation?
• Implications of Planck results for models with local type non-Gaussianity
• Spectator field models in light of spectral index after Planck