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Title: New ekpyrotic cosmology

Abstract

In this paper, we present a new scenario of the early universe that contains a pre-big bang ekpyrotic phase. By combining this with a ghost condensate, the theory explicitly violates the null energy condition without developing any ghostlike instabilities. Thus the contracting universe goes through a nonsingular bounce and evolves smoothly into the expanding post-big bang phase. The curvature perturbation acquires a scale-invariant spectrum well before the bounce in this scenario. It is sourced by the scale-invariant entropy perturbation engendered by two ekpyrotic scalar fields, a mechanism recently proposed by Lehners et al. Since the background geometry is nonsingular at all times, the curvature perturbation remains nearly constant on superhorizon scales. It emerges from the bounce unscathed and imprints a scale-invariant spectrum of density fluctuations in the matter-radiation fluid at the onset of the hot big bang phase. The ekpyrotic potential can be chosen so that the spectrum has a red tilt, in accordance with the recent data from WMAP. As in the original ekpyrotic scenario, the model predicts a negligible gravity wave signal on all observable scales. As such ''new ekpyrotic cosmology'' provides a consistent and distinguishable alternative to inflation to account for the origin of the seeds ofmore » large-scale structure.« less

Authors:
;  [1];  [2]
  1. Perimeter Institute for Theoretical Physics, Waterloo, Ontario, N2L 2Y5 (Canada)
  2. Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6395 (United States)
Publication Date:
OSTI Identifier:
21024011
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 76; Journal Issue: 12; Other Information: DOI: 10.1103/PhysRevD.76.123503; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0556-2821
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COSMOLOGICAL MODELS; COSMOLOGY; DENSITY; DISTURBANCES; ENTROPY; FLUCTUATIONS; GEOMETRY; GRAVITY WAVES; PERTURBATION THEORY; POTENTIALS; SCALAR FIELDS; SCALE INVARIANCE; UNIVERSE

Citation Formats

Buchbinder, Evgeny I, Khoury, Justin, and Ovrut, Burt A. New ekpyrotic cosmology. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.76.123503.
Buchbinder, Evgeny I, Khoury, Justin, & Ovrut, Burt A. New ekpyrotic cosmology. United States. https://doi.org/10.1103/PHYSREVD.76.123503
Buchbinder, Evgeny I, Khoury, Justin, and Ovrut, Burt A. 2007. "New ekpyrotic cosmology". United States. https://doi.org/10.1103/PHYSREVD.76.123503.
@article{osti_21024011,
title = {New ekpyrotic cosmology},
author = {Buchbinder, Evgeny I and Khoury, Justin and Ovrut, Burt A},
abstractNote = {In this paper, we present a new scenario of the early universe that contains a pre-big bang ekpyrotic phase. By combining this with a ghost condensate, the theory explicitly violates the null energy condition without developing any ghostlike instabilities. Thus the contracting universe goes through a nonsingular bounce and evolves smoothly into the expanding post-big bang phase. The curvature perturbation acquires a scale-invariant spectrum well before the bounce in this scenario. It is sourced by the scale-invariant entropy perturbation engendered by two ekpyrotic scalar fields, a mechanism recently proposed by Lehners et al. Since the background geometry is nonsingular at all times, the curvature perturbation remains nearly constant on superhorizon scales. It emerges from the bounce unscathed and imprints a scale-invariant spectrum of density fluctuations in the matter-radiation fluid at the onset of the hot big bang phase. The ekpyrotic potential can be chosen so that the spectrum has a red tilt, in accordance with the recent data from WMAP. As in the original ekpyrotic scenario, the model predicts a negligible gravity wave signal on all observable scales. As such ''new ekpyrotic cosmology'' provides a consistent and distinguishable alternative to inflation to account for the origin of the seeds of large-scale structure.},
doi = {10.1103/PHYSREVD.76.123503},
url = {https://www.osti.gov/biblio/21024011}, journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 12,
volume = 76,
place = {United States},
year = {Sat Dec 15 00:00:00 EST 2007},
month = {Sat Dec 15 00:00:00 EST 2007}
}