Inhomogeneity implies accelerated expansion

@article{Skarke2014InhomogeneityIA,
  title={Inhomogeneity implies accelerated expansion},
  author={Harald Skarke},
  journal={Physical Review D},
  year={2014},
  volume={89},
  pages={043506}
}
  • H. Skarke
  • Published 3 October 2013
  • Physics
  • Physical Review D
The Einstein equations for an inhomogeneous irrotational dust universe are analyzed. A set of mild assumptions, all of which are shared by the standard Friedmann-Lemaitre-Robertson-Walker\char21{}type scenarios, results in a model that depends only on the distribution of scalar spatial curvature. If the shape of this distribution is made to fit the structure of the present Universe, with most of the matter in galaxy clusters and very little in the voids that will eventually dominate the volume… 

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References

SHOWING 1-10 OF 15 REFERENCES

On Average Properties of Inhomogeneous Fluids in General Relativity: Dust Cosmologies

For general relativistic spacetimes filled with irrotational ‘dust’ a generalized form of Friedmann's equations for an ‘effective’ expansion factor aD of inhomogeneous cosmologies is derived.

Accelerated expansion from structure formation

We discuss the physics of backreaction-driven accelerated expansion. Using the exact equations for the behaviour of averages in dust universes, we explain how large-scale smoothness does not imply

On cosmic acceleration without dark energy

We elaborate on the proposal that the observed acceleration of the Universe is the result of the backreaction of cosmological perturbations, rather than the effect of a negative-pressure dark-energy

Onset of cosmological backreaction

Cosmological backreaction has been suggested as an explanation of dark energy and is heavily disputed since. We combine cosmological perturbation theory with Buchert's nonperturbative framework,

Comment about quasi-isotropic solution of Einstein equations near the cosmological singularity

For the case of arbitrary hydrodynamical matter, we generalize the quasi-isotropic solution of Einstein equations near the cosmological singularity, found by Lifshitz and Khalatnikov in 1960 for the

Does the growth of structure affect our dynamical models of the Universe? The averaging, backreaction, and fitting problems in cosmology

Structure occurs over a vast range of scales in the Universe. Our large-scale cosmological models are coarse-grained representations of what exists, which have much less structure than there really

Dark Energy from structure: a status report

The effective evolution of an inhomogeneous universe model in any theory of gravitation may be described in terms of spatially averaged variables. In Einstein’s theory, restricting attention to

The Cosmic Baryon Budget

We present an estimate of the global budget of baryons in all states, with conservative estimates of the uncertainties, based on all relevant information we have been able to marshal. Most of the

Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant

We present spectral and photometric observations of 10 Type Ia supernovae (SNe Ia) in the redshift range 0.16 ≤ z ≤ 0.62. The luminosity distances of these objects are determined by methods that