Publication : t04/032

Modulated fluctuations from hybrid inflation

Bernardeau F. (CEA, DSM, SPhT (Service de Physique Théorique), F-91191 Gif-sur-Yvette, FRANCE)
Kofman L. (Canadian Institute for Theoretical Astrophysics (CITA), University of Toronto, 60 St. George Street, Toronto, M5S 3H8 Ontario, CANADA)
Uzan J.-P. (Laboratoire de Physique Théorique (LPT), CNRS, UMR 8627, Université de Paris-Sud XI, F-91405 Orsay, France)
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 distinguish the modulated from the inflation-driven fluctuations, in particular, their spectral index, modification of the consistency relation and the issue of weak non-Gaussianity.
Année de publication : 2004
Revue : Phys. Rev. D 70 083004 (2004)
DOI : 10.1103/PhysRevD.70.083004
Preprint : arXiv:astro-ph/0403315
Lien :
PACS : 98.70.Vc, 98.80.-k, 02.04.Pc
Numéro Exterieur : CITA-2004-11
Langue : Anglais

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