Can the initial singularity be detected by cosmological tests?

Szydłowski, Marek; Godlowski, Wlodzimierz; Krawiec, Adam; Golbiak, Jacek

doi:10.1103/physrevd.72.063504

Cited by 27 publications

(18 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We find that P (n > 2) ≃ 0.99. It means that bounce is strongly favored over big-bang scenario like to in loop quantum gravity for example [32]. The Fig.…”

Section: Constraining Model Parameters From Snia Datamentioning

confidence: 99%

Dark Matter and Dark Energy as Effects of Modified Gravity

Borowiec

Godlowski

Szydłowski

2007

Int. J. Geom. Methods Mod. Phys.

Self Cite

View full text Add to dashboard Cite

We explain the effect of dark matter (flat rotation curve) using modified gravitational dynamics. We investigate in this context a low energy limit of generalized general relativity with a nonlinear Lagrangian L ∝ R n , where R is the (generalized) Ricci scalar and n is parameter estimated from SNIa data. We estimate parameter β in modified gravitational potential V (r) ∝ − 1 r(1 + ( r rc ) β ). Then we compare value of β obtained from SNIa data with β parameter evaluated from the best fitted rotation curve. We find β ≃ 0.7 which becomes in good agreement with an observation of spiral galaxies rotation curve. We also find preferred value of Ω m,0 from the combined analysis of supernovae data and baryon oscillation peak. We argue that although amount of "dark energy" (of non-substantial origin) is consistent with SNIa data and flat curves of spiral galaxies are reproduces in the framework of modified Einstein's equation we still need substantial dark matter. For comparison predictions of the model with predictions of the ΛCDM concordance model we apply the Akaike and Bayesian information criteria of model selection.

show abstract

“…We find that P (n > 2) ≃ 0.99. It means that bounce is strongly favored over big-bang scenario like to in loop quantum gravity for example [32]. The Fig.…”

Section: Constraining Model Parameters From Snia Datamentioning

confidence: 99%

Dark Matter and Dark Energy as Effects of Modified Gravity

Borowiec

Godlowski

Szydłowski

2007

Int. J. Geom. Methods Mod. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…If some negative component of effective energy density appears in ρ eff (a) then it can never dominate at the early universe and at the late times. If negative energy density scaling like a −m appears in such a way that 3H 2 = m,0 a −m − n,0 a −n + ,0 (where n > m) then we have the case of bouncing cosmological models [47][48][49]. In this model the relation ρ eff (a) ≥ 0 is of course satisfied.…”

Section: Equation Of State Parameter From Distant Supernovae Observatmentioning

confidence: 98%

Equation of state for the Universe from similarity symmetries

2006

Self Cite

View full text Add to dashboard Cite

In this paper we proposed to use the group of analysis of symmetries of the dynamical system to describe the evolution of the Universe. This method is used in searching for the unknown equation of state. It is shown that group of symmetries enforce the form of the equation of state for noninteracting scaling multifluids. We showed that symmetries give rise to the equation of state in the form p = − + w 1 ρ(a) + w 2 a β + 0 and energy density ρ = + ρ 01 a −3(1+w) + ρ 02 a β + ρ 03 a −3 , which is commonly used in cosmology. The FRW model filled with scaling fluid (called homological) is confronted with the observations of distant type Ia supernovae. We found the class of model parameters admissible by the statistical analysis of SNIa data. We showed that the model with scaling fluid fits well to supernovae data. We found that m,0 0.4 and n −1 (β = −3n), which can correspond to (hyper) phantom fluid, and to a high density universe. However if we assume prior that m,0 = 0.3 then the favoured model is close to concordance CDM model. Our results predict that in the considered model with scaling fluids distant type Ia supernovae should be brighter than in the CDM model, while intermediate distant SNIa should be fainter than in the CDM model. We also investigate whether the model with scaling fluid is actually preferred by data over CDM model. As a result we find from the Akaike model selection criterion: it prefers the model with noninteracting scaling fluid.

show abstract

“…These criteria was also used recently by us to show that models with the big-bang scenario are rather prefers over the bouncing scenario [46].…”

Section: Distant Supernovae As Cosmological Probes Dark Energy or Thementioning

confidence: 99%

Which cosmological model—with dark energy or modified FRW dynamics?

Szydłowski¹,

Godlowski²

2006

Physics Letters B

Self Cite

View full text Add to dashboard Cite

Abstract. Recent measurements of distant type Ia supernovae (SNIa) as well as other observations indicate that our universe is in accelerating phase of expansion. In principle there are two alternative explanation for such an acceleration. While in the first approach an unknown form of energy violating the strong energy condition is postulated, in second one some modification of FRW dynamics is postulated. The both approaches are in well agreement with present day observations which is the manifestation of the degeneracy problem appearing in observational cosmology. We use the Akaike (AIC) and Bayesian (BIC) information criteria of model selection to overcome this degeneracy and to determine a model with such a set of parameters which gives the most preferred fit to the SNIa data. We consider five representative evolutional scenarios in each of groups. Among dark energy proposal the ΛCDM model, CDM model with phantom field, CDM model with topological defect, model with Chaplygin gas, and the model with the linear dynamical equation of state parameter. As an alternative prototype scenarios we consider: brane world Dvali Gabadadze Porrati scenario, brane models in Randall-Sundrum scenario, Cardassian models with dust matter and radiation, bouncing model with the cosmological constant and metricaffine gravity (MAG) inspired cosmological models. Applying the model selection criteria we show that both AIC and BIC indicates that additional contribution arises from nonstandard FRW dynamics are not necessary to explain SNIa. Adopting the model selection information criteria we show that the AIC indicates the flat phantom model while BIC indicates both flat phantom and flat ΛCDM models.

show abstract

Can the initial singularity be detected by cosmological tests?

Cited by 27 publications

References 48 publications

Dark Matter and Dark Energy as Effects of Modified Gravity

Dark Matter and Dark Energy as Effects of Modified Gravity

Equation of state for the Universe from similarity symmetries

Which cosmological model—with dark energy or modified FRW dynamics?

Contact Info

Product

Resources

About