Observational backreaction in discrete black holes lattice cosmological models

TL;DR

This paper investigates how discretized black hole lattice models in cosmology affect observational properties like luminosity distance, revealing backreaction effects that challenge standard homogeneous models without violating energy conditions.

Contribution

It introduces a novel analysis of observational backreaction in inhomogeneous black hole lattice models using Sachs formalism, highlighting effects on cosmological observations.

Findings

Increasing the number of sources leads to non-recovery of continuous matter distribution features.

Kinematical backreaction decreases asymptotically, while dynamical and observational backreactions persist.

Electric and magnetic parts of the Weyl tensor influence luminosity distance and scale factor evolution.

Abstract

Applying the Sachs formalism, the optical properties encoded in the distance modulus are studied along curves exhibiting local rotational symmetry for some closed inhomogeneous cosmological models whose mass content is discretized by Schwarzschild-like sources. These models may challenge the concordance model in its use of the distance modulus data of type Ia supernovae, because they do not violate any energy condition. This result relies only on the symmetry properties considered, and not on the way in which the mass is discretized. The models with different number of sources are then compared among themselves and with a Friedmann-Lemaitre-Robertson-Walker model with the same total mass content by introducing a compactness parameter. The analysis shows that observational backreaction occurs because increasing the number of sources the features of a universe with a continuous matter distribution are not recovered. Our models are shown to exhibit a non-trivial relationship between kinematical, dynamical and observational backreactions, the kinematical one being asymptotically decreasing while the latter two are present. Furthermore, the electric part of the Weyl tensor contributes to the luminosity distance by affecting the evolution of the scale factor, while the magnetic part has an indirect role by affecting only the evolution of the former