Cosmic Web Void Structure Evolution Mimics Dark Energyby Tommy on 1/04/2017
I finally got around to getting up to date on the dark energy controversy.
Concordance cosmology without dark energy, Gábor Rácz, László Dobos, Róbert Beck, István Szapudi and István Csabai, Monthly Notices of the Royal Astromical Society Letters slx026 (12 February 2017), DOI:10.1093/mnrasl/slx026
According to the separate universe conjecture, spherically symmetric sub-regions in an isotropic universe behave like mini-universes with their own cosmological parameters. This is an excellent approximation in both Newtonian and general relativistic theories. We estimate local expansion rates for a large number of such regions, and use a scale parameter calculated from the volume-averaged increments of local scale parameters at each time step in an otherwise standard cosmological N-body simulation. The particle mass, corresponding to a coarse graining scale, is an adjustable parameter. This mean field approximation neglects tidal forces and boundary effects, but it is the first step towards a non-perturbative statistical estimation of the effect of non-linear evolution of structure on the expansion rate. Using our algorithm, a simulation with an initial Ωm = 1 Einstein-de~Sitter setting closely tracks the expansion and structure growth history of the ΛCDM cosmology. Due to small but characteristic differences, our model can be distinguished from the ΛCDM model by future precision observations. Moreover, our model can resolve the emerging tension between local Hubble constant measurements and the Planck best-fitting cosmology. Further improvements to the simulation are necessary to investigate light propagation and confirm full consistency with cosmic microwave background observations.
This has been out there for a while, but better late than never!
Update: ESA Euclid Consortium Mission
Euclid Consortium – A Space Mission to Map the Dark Universelifeform@charter.net