On the breakdown of the curvature perturbation ζ during reheating
Abstract
It is known that in single scalar field inflationary models the standard curvature perturbation ζ, which is supposedly conserved at superhorizon scales, diverges during reheating at times 0φdot =, i.e. when the time derivative of the background inflaton field vanishes. This happens because the comoving gauge 0φ=, where φ denotes the inflaton perturbation, breaks down when 0φdot =. The issue is usually bypassed by averaging out the inflaton oscillations but strictly speaking the evolution of ζ is ill posed mathematically. We solve this problem in the free theory by introducing a family of smooth gauges that still eliminates the inflaton fluctuation φ in the Hamiltonian formalism and gives a well behaved curvature perturbation ζ, which is now rigorously conserved at superhorizon scales. At the linearized level, this conserved variable can be used to unambiguously propagate the inflationary perturbations from the end of inflation to subsequent epochs. We discuss the implications of our results for the inflationary predictions.
 Authors:
 Department of Physics, Bo gtilde aziçi University, 34342, Bebek, İstanbul (Turkey)
 Publication Date:
 OSTI Identifier:
 22525899
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 04; Other Information: Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMOLOGICAL INFLATION; DISTURBANCES; FLUCTUATIONS; HAMILTONIANS; INFLATIONARY UNIVERSE; INFLATONS; OSCILLATIONS; SCALAR FIELDS
Citation Formats
Algan, Merve Tarman, Kaya, Ali, and Kutluk, Emine Seyma, Email: merve.tarman@boun.edu.tr, Email: ali.kaya@boun.edu.tr, Email: seymakutluk@gmail.com. On the breakdown of the curvature perturbation ζ during reheating. United States: N. p., 2015.
Web. doi:10.1088/14757516/2015/04/015.
Algan, Merve Tarman, Kaya, Ali, & Kutluk, Emine Seyma, Email: merve.tarman@boun.edu.tr, Email: ali.kaya@boun.edu.tr, Email: seymakutluk@gmail.com. On the breakdown of the curvature perturbation ζ during reheating. United States. doi:10.1088/14757516/2015/04/015.
Algan, Merve Tarman, Kaya, Ali, and Kutluk, Emine Seyma, Email: merve.tarman@boun.edu.tr, Email: ali.kaya@boun.edu.tr, Email: seymakutluk@gmail.com. Wed .
"On the breakdown of the curvature perturbation ζ during reheating". United States.
doi:10.1088/14757516/2015/04/015.
@article{osti_22525899,
title = {On the breakdown of the curvature perturbation ζ during reheating},
author = {Algan, Merve Tarman and Kaya, Ali and Kutluk, Emine Seyma, Email: merve.tarman@boun.edu.tr, Email: ali.kaya@boun.edu.tr, Email: seymakutluk@gmail.com},
abstractNote = {It is known that in single scalar field inflationary models the standard curvature perturbation ζ, which is supposedly conserved at superhorizon scales, diverges during reheating at times 0φdot =, i.e. when the time derivative of the background inflaton field vanishes. This happens because the comoving gauge 0φ=, where φ denotes the inflaton perturbation, breaks down when 0φdot =. The issue is usually bypassed by averaging out the inflaton oscillations but strictly speaking the evolution of ζ is ill posed mathematically. We solve this problem in the free theory by introducing a family of smooth gauges that still eliminates the inflaton fluctuation φ in the Hamiltonian formalism and gives a well behaved curvature perturbation ζ, which is now rigorously conserved at superhorizon scales. At the linearized level, this conserved variable can be used to unambiguously propagate the inflationary perturbations from the end of inflation to subsequent epochs. We discuss the implications of our results for the inflationary predictions.},
doi = {10.1088/14757516/2015/04/015},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 04,
volume = 2015,
place = {United States},
year = {Wed Apr 01 00:00:00 EDT 2015},
month = {Wed Apr 01 00:00:00 EDT 2015}
}

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