What is dust?—Physical foundations of the averaging problem in cosmology

Wiltshire, David L.

doi:10.1088/0264-9381/28/16/164006

Cited by 108 publications

(130 citation statements)

References 133 publications

(371 reference statements)

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“…In the recent years the problem has attracted attention of the researchers in the context of cosmology [2,3,4,5,6,7,8,9,10,11,12,13,14,15]. Obviously in the cosmological setting we assume the existence of a homogeneity scale, which may be as large as 2000Mpc [16], and a complicated, multiscale structure below that.…”

Section: Introductionmentioning

confidence: 99%

Backreaction and continuum limit in a closed universe filled with black holes

Korzyński

2014

Class. Quantum Grav.

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Abstract. We discuss the continuum limit of the initial data for a vacuum, closed cosmological model with black holes as the only sources of the gravitational field. The model we consider is an exact solution of the constraint equations and represents a vacuum universe with a number of black holes placed on a spatial slice of S 3 topology considered at the moment of its largest expansion when the black holes are momentary at rest. We explain how and under what conditions the FLRW metric arises as the continuum limit when the number of black holes contained in the model goes to infinity. We also discuss the relation between the effective cosmological parameters of the model, inferred from the large scale geometry of the spacetime, and the masses of individual black holes. In particular, we prove an estimate for the difference between the total effective mass of the system and the sum of the masses of all black holes, thus quantifying the effects of the inhomogeneities in the matter distribution or the cosmological backreaction.

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Section: Introductionmentioning

confidence: 99%

Backreaction and continuum limit in a closed universe filled with black holes

Korzyński

2014

Class. Quantum Grav.

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“…[109], taking into account the relevance of the voids among the clusters of galaxies, has to be reformulated in terms of the York time.…”

Section: Dark Energy and Other Open Problemsmentioning

confidence: 99%

From Clock Synchronization to Dark Matter as a Relativistic Inertial Effect

Lusanna¹

2014

Springer Proceedings in Physics

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“…The question is to what extent the dynamics of the real universe is described by the homogeneous fluid FLRW models. Due to the nonlinear nature of the Einstein equations this is a difficult problem often referred to as the averaging problem in general relativity [1,2]. It has been extensively discussed in the past but there is still no consensus about its solution (see e.g.…”

Section: Introductionmentioning

confidence: 99%

Analytic analysis of irregular discrete universes

Jolin

Rosquist

2018

Gen Relativ Gravit

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In this work we investigate the dynamics of cosmological models with spherical topology containing up to 600 Schwarzschild black holes arranged in an irregular manner. We solve the field equations by tessellating the 3-sphere into eight identical cells, each having a single edge which is shared by all cells. The shared edge is enforced to be locally rotationally symmetric, thereby allowing for solving the dynamics to high accuracy along this edge. Each cell will then carry an identical (up to parity) configuration which can however have an arbitrarily random distribution. The dynamics of such models is compared to that of previous works on regularly distributed black holes as well as with the standard isotropic dust models of the FLRW type. The irregular models are shown to have richer dynamics than that of the regular models. The randomization of the distribution of the black holes is done both without bias and also with a certain clustering bias. The geometry of the initial configuration of our models is shown to be qualitatively different from the regular case in the way it approaches the isotropic model.

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What is dust?—Physical foundations of the averaging problem in cosmology

Cited by 108 publications

References 133 publications

Backreaction and continuum limit in a closed universe filled with black holes

Backreaction and continuum limit in a closed universe filled with black holes

From Clock Synchronization to Dark Matter as a Relativistic Inertial Effect

Analytic analysis of irregular discrete universes

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