Rastall’s cosmology and its observational constraints

Abstract

The Rastall's theory is a modification of General Relativity touching one of the cornestone of gravity theory: the conservation laws. In Rastall's theory, the energy-momentum tensor is not conserved anymore, depending now on the gradient of the Ricci curvature. In this sense, this theory can be seen as a classical implementation of quantum effects in a curved background space-time. We exploit this structure in order to reproduce some results of an effective theory of quantum loop cosmology. Later, we propose a model for the dark sector of the universe. In this case, the corresponding ΛCDM model appears as the only model consistent with observational data.

Neutron stars in Rastall gravity

“…However, it seems non-trivial to explain the nature of such new source. This can be phenomenologically viewed as the appearance of quantum effects in the classical context, as discussed in [6]. Interestingly, the issue of nonconservation of T µν is a feature also found for instance in diffusion models [7] and its connection to modified gravity theories has been discussed in literature in Refs.…”

“…Note that we recall in this plot the usual definition for mass as presented in (6). The labels in the figure indicate the η values.…”

Rastall gravity extension of the standard $$\Lambda $$CDM model: theoretical features and observational constraints

“…[89] impose the Rastall gravity contributions from the non-conservation of dust upon DE which makes it clustering. Then, it is suggested in [94,95] that this model resembles the standard CDM model at the background level (with an not strictly constrained, provided that the DE yields an equation of state parameter very close to minus unity), while in [96] that the evolution of the growth index displays a significant deviation from that in the standard CDM model. One of the main motivations behind such attempts is that observational signatures of non-conservation in the dark sector is expected in the non-linear regime on intermediate or small scales, and is not inconsistent with the currently available cosmological data (see [97] for details).…”

On Gödel-type solution in Rastall's gravity

“…The latest motivation for studying Rastall's theory is that it can be seen as a classical implementation of quantum effects in a curved space-time. Some analyzes in this context can be seen in [11] and [12].…”