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Title: Behavior of nonlinear anisotropies in bouncing Bianchi I models of loop quantum cosmology

Abstract

In homogeneous and isotropic loop quantum cosmology, gravity can behave repulsively at Planckian energy densities leading to the replacement of the big bang singularity with a big bounce. Yet in any bouncing scenario it is important to include nonlinear effects from anisotropies which typically grow during the collapsing phase. We investigate the dynamics of a Bianchi I anisotropic model within the framework of loop quantum cosmology. Using effective semiclassical equations of motion to study the dynamics, we show that the big bounce is still predicted with only differences in detail arising from the inclusion of anisotropies. We show that the anisotropic shear term grows during the collapsing phase, but remains finite through the bounce. Immediately following the bounce, the anisotropies decay and with the inclusion of matter with equation of state w<+1, the universe isotropizes in the expanding phase.

Authors:
 [1];  [1]
  1. Institute for Gravitational Physics and Geometry, Physics Department, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)
Publication Date:
OSTI Identifier:
21032462
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 76; Journal Issue: 8; Other Information: DOI: 10.1103/PhysRevD.76.084015; (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; ANISOTROPY; COSMOLOGY; ENERGY DENSITY; EQUATIONS OF MOTION; EQUATIONS OF STATE; GRAVITATION; NONLINEAR PROBLEMS; QUANTUM FIELD THEORY; SEMICLASSICAL APPROXIMATION; SHEAR; SINGULARITY; UNIVERSE

Citation Formats

Chiou, D -W, Vandersloot, Kevin, and Institute for Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 2EG. Behavior of nonlinear anisotropies in bouncing Bianchi I models of loop quantum cosmology. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.76.084015.
Chiou, D -W, Vandersloot, Kevin, & Institute for Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 2EG. Behavior of nonlinear anisotropies in bouncing Bianchi I models of loop quantum cosmology. United States. https://doi.org/10.1103/PHYSREVD.76.084015
Chiou, D -W, Vandersloot, Kevin, and Institute for Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 2EG. 2007. "Behavior of nonlinear anisotropies in bouncing Bianchi I models of loop quantum cosmology". United States. https://doi.org/10.1103/PHYSREVD.76.084015.
@article{osti_21032462,
title = {Behavior of nonlinear anisotropies in bouncing Bianchi I models of loop quantum cosmology},
author = {Chiou, D -W and Vandersloot, Kevin and Institute for Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 2EG},
abstractNote = {In homogeneous and isotropic loop quantum cosmology, gravity can behave repulsively at Planckian energy densities leading to the replacement of the big bang singularity with a big bounce. Yet in any bouncing scenario it is important to include nonlinear effects from anisotropies which typically grow during the collapsing phase. We investigate the dynamics of a Bianchi I anisotropic model within the framework of loop quantum cosmology. Using effective semiclassical equations of motion to study the dynamics, we show that the big bounce is still predicted with only differences in detail arising from the inclusion of anisotropies. We show that the anisotropic shear term grows during the collapsing phase, but remains finite through the bounce. Immediately following the bounce, the anisotropies decay and with the inclusion of matter with equation of state w<+1, the universe isotropizes in the expanding phase.},
doi = {10.1103/PHYSREVD.76.084015},
url = {https://www.osti.gov/biblio/21032462}, journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 8,
volume = 76,
place = {United States},
year = {Mon Oct 15 00:00:00 EDT 2007},
month = {Mon Oct 15 00:00:00 EDT 2007}
}