Sensitivity of the cosmic microwave background anisotropy to initial conditions in quintessence cosmology

Dave, R.; Caldwell, Robert R.; Steinhardt, Paul J.

doi:10.1103/physrevd.66.023516

Cited by 65 publications

(67 citation statements)

References 26 publications

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“…At subhorizon scales the effective (geometrical in our case) dark energy component is expected to be smooth and thus it is fair to consider perturbations only on the matter component of the cosmic fluid [38]. The evolution equation of the matter fluctuations δ m ≡ δρ m /ρ m , for cosmological models where the dark energy fluid has a vanishing anisotropic stress and the matter fluid is not coupled to other matter species (see Refs.…”

Section: The Linear Matter Fluctuationsmentioning

confidence: 99%

Cosmological equivalence between the Finsler-Randers space-time and the DGP gravity model

Basilakos

Stavrinos

2013

Phys. Rev. D

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We perform a detailed comparison between the Finsler-Randers cosmological model and the Dvali, Gabadadze and Porrati braneworld model. If we assume that the spatial curvature is strictly equal to zero then we prove the following interesting proposition: despite the fact that the current cosmological models have a completely different geometrical origin they share exactly the same Hubble expansion. This implies that the Finsler-Randers model is cosmologically equivalent with that of the DGP model as far as the cosmic expansion is concerned. At the perturbative level we find that the Finsler-Randers growth index of matter perturbations is γF R ≃ 9/14 which is somewhat lower than that of DGP gravity (γDGP ≃ 11/16) implying that the growth factor of the Finsler-Randers model is slightly different (∼ 0.1 − 2%) from the one provided by the DGP gravity model. 98.80.Bp, 98.65.Dx, 95.35.+d, 95.36.+x

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Section: The Linear Matter Fluctuationsmentioning

confidence: 99%

Cosmological equivalence between the Finsler-Randers space-time and the DGP gravity model

Basilakos

Stavrinos

2013

Phys. Rev. D

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“…(6) and (7). Combining these equations, the evolution of density perturbations in the IQ field are described by a driven damped harmonic oscillator, where the driving term is the gravitational field [27]. After a brief transient period, the evolution is dominated by the inhomogeneous solution and is insensitive to the initial amplitude.…”

Section: Observational Constraints On the Matter-quintessence Comentioning

confidence: 99%

Observational constraints on interacting quintessence models

2005

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We determine the range of parameter space of a Interacting Quintessence Model that best fits the recent WMAP measurements of Cosmic Microwave Background temperature anisotropies. We only consider cosmological models with zero spatial curvature. We show that if the quintessence scalar fields decays into cold dark matter at a rate that brings the ratio of matter to dark energy constant at late times, the cosmological parameters required to fit the CMB data are: dark energy density Ω x = 0.43 ± 0.12, baryon fraction Ω b = 0.08 ± 0.01, slope of the matter power spectrum at large scales n s = 0.98±0.02 and Hubble constant H 0 = 56±4 km/s/M pc. The data prefers a dark energy component with a dimensionless decay rate parameter c 2 = 0.005 and non-interacting models are consistent with the data only at the 99.9% confidence level. Using the Bayesian InformationCriteria we show that this extra parameter fits the data better than models with no interaction.The quintessence equation of state parameter is less constrained; i.e., the data sets an upper limit w x ≤ −0.86 at the same level of significance. When the WMAP anisotropy data are combined with supernovae data, the density parameter of dark energy increases to Ω x ≃ 0.68 while c 2 augments to 6.3 × 10 −3 . Models with quintessence decaying into dark matter provide a clean explanation for the coincidence problem and are a viable cosmological model, compatible with observations of the CMB, with testable predictions. Accurate measurements of baryon fraction and/or of matter density independent of the CMB data, would support/disprove these models. *

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“…Although it has been shown that the dark energy fluid does not cluster on scales smaller than 100Mpc [86], it is also interesting to consider the case when the dark energy clusters along with the dark matter. Such a behavior is expected in models of interacting dark energy with dark matter and may also be a result of the gravitational interaction between nonlinearly clustered dark matter and dark energy.…”

Section: B Inhomogeneous Dark Energymentioning

confidence: 99%

Spherical collapse model and cluster formation beyond theΛcosmology: Indications for a clustered dark energy?

2009

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We generalize the small scale dynamics of the universe by taking into account models with an equation of state which evolves with time, and provide a complete formulation of the cluster virialization attempting to address the nonlinear regime of structure formation. In the context of the current dark energy models, we find that galaxy clusters appear to form at z ∼ 1 − 2, in agreement with previous studies. Also, we investigate thoroughly the evolution of spherical matter perturbations, as the latter decouple from the background expansion and start to "turn around" and finally collapse. Within this framework, we find that the concentration parameter depends on the choice of the considered dark energy (homogeneous or clustered). In particular, if the distribution of the dark energy is clustered then we produce more concentrated structures with respect to the homogeneous dark energy. Finally, comparing the predicted concentration parameter with the observed concentration parameter, measured for four massive galaxy clusters, we find that the scenario which contains a pure homogeneous dark energy is unable to reproduce the data. The situation becomes somewhat better in the case of an inhomogeneous (clustered) dark energy.PACS numbers: 98.80.-k, 95.35.+d, 95.36.+x

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Sensitivity of the cosmic microwave background anisotropy to initial conditions in quintessence cosmology

Cited by 65 publications

References 26 publications

Cosmological equivalence between the Finsler-Randers space-time and the DGP gravity model

Cosmological equivalence between the Finsler-Randers space-time and the DGP gravity model

Observational constraints on interacting quintessence models

Spherical collapse model and cluster formation beyond theΛcosmology: Indications for a clustered dark energy?

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