Article

# Reinterpreting dark energy through backreaction: the minimally coupled morphon field

12/2006; DOI: 10.1142/9789812834300_0268

Source: arXiv

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**ABSTRACT:**We explore the backreaction model based on the template metric proposed in Larena et al. (2008) constraining the matter density parameter $\Omega_m^{D_0}$ and the Dark Energy parameter $w$ with recent data. We provide constraints based on Supernovae Ia from the SNLS and the Union2.1 catalogs, confirming that the backreacted Universe should have a higher matter density than the corresponding Friedmaniann one. Angular diameter distances from clusters data confirm the same feature. Finally we combine these results with constraints obtained from the position of the first three peaks and the first dip of the CMB power spectrum, fitting WMAP-9 and Planck data. We find that an inconsistency arises in predicting the scale factor at recombination, leading to a backreacted Universe with lower matter density, in contradiction with results produced by SnIa and clusters. The same behavior is confirmed by analyzing the CMB-shift parameters from WMAP-9. We conclude exploring qualitatively the motivations of this inconsistency.Journal of Cosmology and Astroparticle Physics 05/2014; 2014(12). · 5.88 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**New statistical ensembles of classical extreme black holes are introduced. Each ensemble is proven to represent a non extreme, finite temperature black hole. This mean or average black hole is surrounded by a mean electromagnetic field and a so-called apparent matter, which is the large scale trace of the averaged upon small scale fluctuations of the gravitational and electromagnetic fields. However, the total mass and the total charge of space–time is not modified by the averaging.Physica A: Statistical Mechanics and its Applications 03/2009; · 1.72 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**We derive the redshift and the angular diameter distance in rotationless dust universes which are statistically homogeneous and isotropic, but have otherwise arbitrary geometry. The calculation from first principles shows that the Dyer-Roeder approximation does not correctly describe the effect of clumping. Instead, the redshift and the distance are determined by the average expansion rate, the matter density today and the null geodesic shear. In particular, the position of the CMB peaks is consistent with significant spatial curvature provided the expansion history is sufficiently close to the spatially flat LambdaCDM model. Comment: 33 pages. v2: Published version. Corrected typosJournal of Cosmology and Astroparticle Physics 12/2008; · 5.88 Impact Factor

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