Nonsingular ekpyrotic/cyclic model in loop quantum cosmology

被引:39
作者
Cailleteau, Thomas [1 ,2 ]
Singh, Parampreet [3 ]
Vandersloot, Kevin [2 ]
机构
[1] UJF, Lab Phys Subatom & Cosmol, CNRS, IN2P3,INPG, F-38026 Grenoble, France
[2] Univ Portsmouth, Inst Cosmol & Gravitat, Portsmouth P01 2EG, Hants, England
[3] Perimeter Inst Theoret Phys, Waterloo, ON N2L 2Y5, Canada
来源
PHYSICAL REVIEW D | 2009年 / 80卷 / 12期
关键词
D O I
10.1103/PhysRevD.80.124013
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
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.
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页数:14
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