Bouncing loop quantum cosmology from F(T) gravity
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hdl:2117/20717
Tipus de documentArticle
Data publicació2013-05
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Abstract
The big bang singularity could be understood as a breakdown of Einstein’s general relativity at very
high energies. By adopting this viewpoint, other theories that implement Einstein cosmology at high
energies might solve the problem of the primeval singularity. One of them is loop quantum cosmology
(LQC) with a small cosmological constant that models a universe moving along an ellipse, which prevents
singularities like the big bang or the big rip, in the phase space
ð
H;
Þ
, where
H
is the Hubble parameter
and
the energy density of the universe. Using LQC one considers a model universe filled by radiation
and matter where, due to the cosmological constant, there are a de Sitter and an anti–de Sitter solution.
This means that one obtains a bouncing nonsingular universe which is in the contracting phase at early
times. After leaving this phase, i.e., after bouncing, it passes trough a radiation- and matter-dominated
phase and finally at late times it expands in an accelerated way (current cosmic acceleration). This model
does not suffer from the horizon and flatness problems as in big bang cosmology, where a period of
inflation that increases the size of our universe in more than 60 e-folds is needed in order to solve both
problems. The model has two mechanisms to avoid these problems: the evolution of the universe through
a contracting phase and a period of super inflation (
_
H>
0
)
CitacióAmoros, J.; Haro, J.; Odintsov, S. Bouncing loop quantum cosmology from F(T) gravity. "Physical review D", Maig 2013, vol. 87, núm. 10, p. 104037-1-104037-10.
ISSN0556-2821
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