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Title: Converting entropy to curvature perturbations after a cosmic bounce

Abstract

We study two-field bouncing cosmologies in which primordial perturbations are created in either an ekpyrotic or a matter-dominated contraction phase. We use a non-singular ghost condensate bounce model to follow the perturbations through the bounce into the expanding phase of the universe. In contrast to the adiabatic perturbations, which on large scales are conserved across the bounce, entropy perturbations can grow significantly during the bounce phase. If they are converted into adiabatic/curvature perturbations after the bounce, they typically form the dominant contribution to the observed temperature fluctuations in the microwave background, which can have several beneficial implications. For ekpyrotic models, this mechanism loosens the constraints on the amplitude of the ekpyrotic potential while naturally suppressing the intrinsic amount of non-Gaussianity. For matter bounce models, the mechanism amplifies the scalar perturbations compared to the associated primordial gravitational waves.

Authors:
; ; ;  [1]
  1. Max Planck Institute for Gravitational Physics, Albert Einstein Institute,14476 Potsdam-Golm (Germany)
Publication Date:
Sponsoring Org.:
SCOAP3, CERN, Geneva (Switzerland)
OSTI Identifier:
22572160
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2016; Journal Issue: 10; Other Information: PUBLISHER-ID: JCAP10(2016)005; OAI: oai:repo.scoap3.org:17553; cc-by Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COSMOLOGICAL INFLATION; DISTURBANCES; ENTROPY; GRAVITATIONAL WAVES; INFLATIONARY UNIVERSE; MICROWAVE RADIATION; PERTURBATION THEORY; UNIVERSE

Citation Formats

Fertig, Angelika, Lehners, Jean-Luc, Mallwitz, Enno, and Wilson-Ewing, Edward. Converting entropy to curvature perturbations after a cosmic bounce. United States: N. p., 2016. Web. doi:10.1088/1475-7516/2016/10/005.
Fertig, Angelika, Lehners, Jean-Luc, Mallwitz, Enno, & Wilson-Ewing, Edward. Converting entropy to curvature perturbations after a cosmic bounce. United States. doi:10.1088/1475-7516/2016/10/005.
Fertig, Angelika, Lehners, Jean-Luc, Mallwitz, Enno, and Wilson-Ewing, Edward. Tue . "Converting entropy to curvature perturbations after a cosmic bounce". United States. doi:10.1088/1475-7516/2016/10/005.
@article{osti_22572160,
title = {Converting entropy to curvature perturbations after a cosmic bounce},
author = {Fertig, Angelika and Lehners, Jean-Luc and Mallwitz, Enno and Wilson-Ewing, Edward},
abstractNote = {We study two-field bouncing cosmologies in which primordial perturbations are created in either an ekpyrotic or a matter-dominated contraction phase. We use a non-singular ghost condensate bounce model to follow the perturbations through the bounce into the expanding phase of the universe. In contrast to the adiabatic perturbations, which on large scales are conserved across the bounce, entropy perturbations can grow significantly during the bounce phase. If they are converted into adiabatic/curvature perturbations after the bounce, they typically form the dominant contribution to the observed temperature fluctuations in the microwave background, which can have several beneficial implications. For ekpyrotic models, this mechanism loosens the constraints on the amplitude of the ekpyrotic potential while naturally suppressing the intrinsic amount of non-Gaussianity. For matter bounce models, the mechanism amplifies the scalar perturbations compared to the associated primordial gravitational waves.},
doi = {10.1088/1475-7516/2016/10/005},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 10,
volume = 2016,
place = {United States},
year = {Tue Oct 04 00:00:00 EDT 2016},
month = {Tue Oct 04 00:00:00 EDT 2016}
}