QG3 - Loop quantum gravity: cosmology and black holes |
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Speaker |
Wang, Anzhong |
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Coauthors |
Bao-Fei Li and Parampreet Singh |
| Talk Title |
Qualitative dynamics in pre-inflationary universe from loop quantum gravity |
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Abstract |
We systematically study the pre-inflationary dynamics of the universe in the framework of loop quantum gravity. Due to the the quantization ambiguities, three different models are resulted. In all three models, it turns out that the replacement of the big bang singularity by a quantum bounce is a robust feature against the quantization ambiguities, although the details (near the bounce) are different in each of these models. In particular, the bounce takes place at different critical energy densities. We carry out numerical simulations for several popular inflationary potentials. In each of the three models, we find universal properties of the background evolution for the kinetic dominated bounce, irrespective of the nature of the inflationary potentials. Specifically, in the post-bounce stage but before the Universe enters the reheating phase, three distinctive phases, bouncing, transition and slow-roll inflation, are identified, and shown explicitly that the evolution of the expansion factor of the universe in the bouncing phase is independent of the inflationary potentials and can be given explicitly, as longer as the evolution is dominated at the bounce by the kinetic energy of the inflaton. Considering the wide range of initial conditions that lead to the slow-roll inflation with adequate e-folds (for either kinetic energy or potential energy dominated pounce), we find that inflation is a generic outcome in all these three models. |
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