Nonsingular ekpyrotic/cyclic model in loop quantum cosmology
- Laboratoire de Physique Subatomique et de Cosmologie, UJF, CNRS-IN2P3-INPG 53 Avenue des Martyrs, 38026 Grenoble Cedex (France)
- Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, Ontario N2L 2Y5 (Canada)
- Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth P01 2EG (United Kingdom)
We study the role of nonperturbative quantum gravity effects in the ekpyrotic/cyclic model using the effective framework of loop quantum cosmology in the presence of anisotropies. We show that quantum geometric modifications to the dynamical equations near the Planck scale as understood in the quantization of Bianchi-I spacetime in loop quantum cosmology lead to the resolution of classical singularity and result in a nonsingular transition of the Universe from the contracting to the expanding branch. In the Planck regime, the Universe undergoes multiple small bounces and the anisotropic shear remains bounded throughout the evolution. A novel feature, which is absent for isotropic models, is a natural turn-around of the moduli field from the negative region of the potential leading to a cyclic phenomena as envisioned in the original paradigm. Our work suggests that incorporation of quantum gravitational effects in the ekpyrotic/cyclic model may lead to a viable scenario without any violation of the null energy condition.
- OSTI ID:
- 21313605
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 80, Issue 12; Other Information: DOI: 10.1103/PhysRevD.80.124013; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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