Avoiding the Big Bang Singularity with Palatini f(R) Theories

Barragán, Carlos Fernando Latorre; Olmo, Gonzalo J.; Sanchis-Alepuz, Hèlios

doi:10.48550/arxiv.1002.3919

Cited by 8 publications

(13 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Note that in Ref. [56] the authors have corrected a mistake regarding nonzero spatial curvature in Ref. [46], and there the considerations are in accordance with ours here.…”

Section: Quadratic Modelsupporting

confidence: 82%

Bouncing Palatini cosmologies and their perturbations

Koivisto

2010

Phys. Rev. D

View full text Add to dashboard Cite

Nonsingular cosmologies are investigated in the framework of f(R) gravity within the first order formalism. General conditions for bounces in isotropic and homogeneous cosmology are presented. It is shown that only a quadratic curvature correction is needed to predict a bounce in a flat or to describe cyclic evolution in a curved dust-filled universe. Formalism for perturbations in these models is set up. In the simplest cases, the perturbations diverge at the turnover. Conditions to obtain smooth evolution are derived.Comment: 7 pages, 1 figure. v2: added references

show abstract

“…Note that in Ref. [56] the authors have corrected a mistake regarding nonzero spatial curvature in Ref. [46], and there the considerations are in accordance with ours here.…”

Section: Quadratic Modelsupporting

confidence: 82%

Bouncing Palatini cosmologies and their perturbations

Koivisto

2010

Phys. Rev. D

View full text Add to dashboard Cite

show abstract

“…The emergence of wormholes in scenarios with self-gravitating fields allows to interpret such solutions as geons in Wheeler's sense [47], which further supports their topological nature. It should be noted that the quadratic f (R) model considered here also exhibits nonsingular cosmological solutions with a bounce [48][49][50] (see also [32,51] for related results). Whether such bouncing solutions can be related to the interior of the black hole solutions obtained here is an issue that will be explored elsewhere.…”

Section: Wormhole Geometrymentioning

confidence: 53%

Nonsingular Black Holes in ƒ (R) Theories

2015

View full text Add to dashboard Cite

Abstract:We study the structure of a family of static, spherically symmetric space-times generated by an anisotropic fluid and governed by a particular type of f (R) theory. We find that for a range of parameters with physical interest, such solutions represent black holes with the central singularity replaced by a finite size wormhole. We show that time-like geodesics and null geodesics with nonzero angular momentum never reach the wormhole throat due to an infinite potential barrier. For null radial geodesics, it takes an infinite affine time to reach the wormhole. This means that the resulting space-time is geodesically complete and, therefore, nonsingular despite the generic existence of curvature divergences at the wormhole throat.

show abstract

“…The quadratic Palatini model introduced above, however, can avoid this situation. For that model, (1.61) becomes [Barragan et al, 2009a, Barragan et al, 2009b, Olmo, 2010] .62) This expression recovers the linear dependence on ρ of GR in the limit |R/R P | ≪ 1. However, if R reaches the value R b = −R P /2, then H 2 vanishes and the expansion factor a(t) reaches a minimum.…”

Section: Palatini Approach To Modified Gravitymentioning

confidence: 77%