Modulated fluctuations from hybrid inflation

By F. Bernardeau, Lev Kofman, Jean-Philippe Uzan. 2004

134 citations recorded by the source corpus.

Inflation universally produces classical almost scale free Gaussian inhomogeneities of any light scalars. Assuming the coupling constants at the time of inflation depend on some light moduli fields, we encounter the generation of modulated cosmological fluctuations from (p)reheating. This is an alternative mechanism to generate observable (almost) scale free adiabatic metric perturbations. We extend this idea to the class of hybrid inflation, where the bifurcation value of the inflaton is modulated by the spatial inhomogeneities of the couplings. As a result, the symmetry breaking after inflation occurs not simultaneously in space but with the time laps in different Hubble patches inherited from the long-wavelength moduli inhomogeneities. To calculate modulated fluctuations we introduce techniques of general relativistic matching conditions for metric perturbations at the time hypersurface where the equation of state after inflation undergoes a jump, without evoking the detailed microscopic physics, as far as it justifies the jump. We apply this theory to the modulated fluctuations from the hybrid and chaotic inflations. We discuss what distinguishes the modulated from the inflation-driven fluctuations, in particular, their spectral index, modification of the consistency relation, and the issue of weak non-Gaussianity.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/3a4ca674eefcb3ece876aae4b19e647d71e63020

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In Astronomy and Astrophysics

1. A. Banday
2. H. Eriksen
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Citations in the corpus

• Planck 2018 results. IX. Constraints on primordial non-Gaussianity (2019, background): “2009) or due to fluctuations in the decay rate or interactions of the inflaton field, as realized in modulated (p)reheating and modulated hybrid inflationary models (Kofman 2003; Dvali et al. 2004a,b; Bernardeau et al. 2004; Zaldarriaga 2004; Lyth 2005; Salem 2005; Lyth & Riotto 2006; Kolb et al. 20”
• Planck 2015 results. XVII. Constraints on primordial non-Gaussianity (2015, unknown): “…2009) or from fluctuations in the inflaton decay rate or interactions, as found in modulated (p)reheating and modulated hybrid inflation (Kofman 2003; Dvali et al. 2004a,b; Bernardeau et al. 2004; Zaldarriaga 2004; Lyth 2005; Salem 2005; Lyth & Riotto 2006; Kolb et al. 2006; Cicoli et al. 2012).”
• Large-scale bias and efficient generation of initial conditions for nonlocal primordial non-Gaussianity (2011, background): “reheating period when the inflaton energy density is converted into standard model particles with a fluctuating decay rate [5].”
• Inflation and string cosmology (2001, background): “One may also produce adiabatic perturbations by perturbing effective coupling constants, which modulates the process of reheating [38, 39].”
• Varying Constants, Gravitation and Cosmology (2010, background): “More speculative, is the effect that such fluctuations can have during preheating after inflation since the decay rate of the inflaton in particles may fluctuate on large scales [293, 294].”