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Title: Bouncing Galileon cosmologies

Abstract

We present nonsingular, homogeneous and isotropic bouncing solutions of the conformal Galileon model. We show that such solutions necessarily begin with a radiation-dominated contracting phase. This is followed by a quintom scenario in which the background equation of state crosses the cosmological constant boundary allowing for a nonsingular bounce which in turn is followed by Galilean Genesis. We analyze the spectrum of cosmological perturbations in this background. Our results show that the fluctuations evolve smoothly and without any pathology, but the adiabatic modes form a blue tilted spectrum. In order to achieve a scale-invariant primordial power spectrum as required by current observations, we introduce a light scalar field coupling to the Galileon kinetically. We find two couplings which yield a scale-invariant spectrum, one of which requires a fine tuning of the initial conditions. This model also predicts a blue tilted spectrum of gravitational waves stemming from quantum vacuum fluctuations in the contracting phase.

Authors:
 [1]; ; ;  [2];  [3]
  1. Department of Physics, Chung-Yuan Christian University, Chung-li 320, Taiwan (China)
  2. TPCSF, Institute of High Energy Physics, CAS, P.O. Box 918-4, Beijing 100049 (China)
  3. Department of Physics, Nanjing University, Nanjing 210093 (China)
Publication Date:
OSTI Identifier:
22279694
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2011; Journal Issue: 10; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMOLOGICAL CONSTANT; COSMOLOGY; DISTURBANCES; ENERGY SPECTRA; EQUATIONS OF STATE; FLUCTUATIONS; GRAVITATIONAL WAVES; MATHEMATICAL SOLUTIONS; SCALAR FIELDS; SCALE INVARIANCE; VISIBLE RADIATION

Citation Formats

Qiu, Taotao, Evslin, Jarah, Cai, Yi-Fu, Zhang, Xinmin, and Li, Mingzhe, E-mail: xsjqiu@gmail.com, E-mail: jarah@ihep.ac.cn, E-mail: ycai21@asu.edu, E-mail: limz@nju.edu.cn, E-mail: xmzhang@ihep.ac.cn. Bouncing Galileon cosmologies. United States: N. p., 2011. Web. doi:10.1088/1475-7516/2011/10/036.
Qiu, Taotao, Evslin, Jarah, Cai, Yi-Fu, Zhang, Xinmin, & Li, Mingzhe, E-mail: xsjqiu@gmail.com, E-mail: jarah@ihep.ac.cn, E-mail: ycai21@asu.edu, E-mail: limz@nju.edu.cn, E-mail: xmzhang@ihep.ac.cn. Bouncing Galileon cosmologies. United States. doi:10.1088/1475-7516/2011/10/036.
Qiu, Taotao, Evslin, Jarah, Cai, Yi-Fu, Zhang, Xinmin, and Li, Mingzhe, E-mail: xsjqiu@gmail.com, E-mail: jarah@ihep.ac.cn, E-mail: ycai21@asu.edu, E-mail: limz@nju.edu.cn, E-mail: xmzhang@ihep.ac.cn. Sat . "Bouncing Galileon cosmologies". United States. doi:10.1088/1475-7516/2011/10/036.
@article{osti_22279694,
title = {Bouncing Galileon cosmologies},
author = {Qiu, Taotao and Evslin, Jarah and Cai, Yi-Fu and Zhang, Xinmin and Li, Mingzhe, E-mail: xsjqiu@gmail.com, E-mail: jarah@ihep.ac.cn, E-mail: ycai21@asu.edu, E-mail: limz@nju.edu.cn, E-mail: xmzhang@ihep.ac.cn},
abstractNote = {We present nonsingular, homogeneous and isotropic bouncing solutions of the conformal Galileon model. We show that such solutions necessarily begin with a radiation-dominated contracting phase. This is followed by a quintom scenario in which the background equation of state crosses the cosmological constant boundary allowing for a nonsingular bounce which in turn is followed by Galilean Genesis. We analyze the spectrum of cosmological perturbations in this background. Our results show that the fluctuations evolve smoothly and without any pathology, but the adiabatic modes form a blue tilted spectrum. In order to achieve a scale-invariant primordial power spectrum as required by current observations, we introduce a light scalar field coupling to the Galileon kinetically. We find two couplings which yield a scale-invariant spectrum, one of which requires a fine tuning of the initial conditions. This model also predicts a blue tilted spectrum of gravitational waves stemming from quantum vacuum fluctuations in the contracting phase.},
doi = {10.1088/1475-7516/2011/10/036},
journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 10,
volume = 2011,
place = {United States},
year = {2011},
month = {10}
}