Virialisationinduced curvature as a physical explanation for dark energy
Abstract
The geometry of the dark energy and cold dark matter dominated cosmological model (ΛCDM) is commonly assumed to be given by a FriedmannLemaîtreRobertsonWalker (FLRW) metric, i.e. it assumes homogeneity in the comoving spatial section. The homogeneity assumption fails most strongly at (i) small distance scales and (ii) recent epochs, implying that the FLRW approximation is most likely to fail at these scales. We use the virialisation fraction to quantify (i) and (ii), which approximately coincide with each other on the observational past light cone. For increasing time, the virialisation fraction increases above 10% at about the same redshift ( ~ 13) at which Ω_{Λ} grows above 10% ( ≈ 1.8). Thus, instead of nonzero Ω_{Λ}, we propose an approximate, generalrelativistic correction to the matterdominated (Ω_{m} = 1,Ω_{Λ} = 0), homogeneous metric (Einsteinde Sitter, EdS). A lowredshift effective matterdensity parameter of Ω_{m}^{eff}(0) = 0.26±0.05 is inferred. Over redshifts 0 < z < 3, the distance modulus of the virialisationcorrected EdS model approximately matches the ΛCDM distance modulus. This rough approximation assumes ``old physics'' (general relativity), not ``new physics''. Thus, pending more detailed calculations, we strengthen the claim that ``dark energy'' should be considered as an artefact of emerging average curvature in the voiddominated Universe, via a novel approach that quantifies the relation between virialisation and average curvature evolution.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 October 2013
 DOI:
 10.1088/14757516/2013/10/043
 arXiv:
 arXiv:1303.4444
 Bibcode:
 2013JCAP...10..043R
 Keywords:

 Astrophysics  Cosmology and Extragalactic Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 25 pages, 8 figures, 1 table, octave script included in arXiv source package