Big-bounce cosmology from quantum gravity: The case of a cyclical Bianchi I universe
arXiv:1607.04481 · doi:10.1103/PhysRevD.94.023519
Abstract
We analyse the classical and quantum dynamics of a Bianchi I model in the presence of a small negative cosmological constant characterizing its evolution in term of the dust-time dualism. We demonstrate that in a canonical metric approach, the cosmological singularity is removed in correspondence to a positive defined value of the dust energy density. Furthermore, the quantum Big-Bounce is connected to the Universe turning point via a well-defined semiclassical limit. Then we can reliably infer that the proposed scenario is compatible with a cyclical Universe picture. We also show how, when the contribution of the dust energy density is sufficiently high, the proposed scenario can be extended to the Bianchi IX cosmology and therefore how it can be regarded as a paradigm for the generic cosmological model. Finally, we investigate the origin of the observed cut-off on the cosmological dynamics, demonstrating how the Big-Bounce evolution can be mimicked by the same semiclassical scenario, where the negative cosmological constant is replaced via a polymer discretization of the Universe volume. A direct proportionality law between such two parameters is then established.
15 pages, 9 figures
References in corpus (10)
- Extended Theories of Gravity and their Cosmological and Astrophysical Applications
- Loop Quantum Cosmology: An Overview
- Polymer Quantum Mechanics and its Continuum Limit
- The Matter Bounce Alternative to Inflationary Cosmology
- The Big-Bang Singularity in the framework of a Generalized Uncertainty Principle
- Hamiltonian and physical Hilbert space in polymer quantum mechanics
- Evolutionary Quantum Dynamics of a Generic Universe
- Definition of a time variable with Entropy of a perfect fluid in Canonical Quantum Gravity
- Nonsingular cosmology from evolutionary quantum gravity
- Cosmological implications of an evolutionary quantum gravity