Alternatives to $\Lambda$: Torsion, Generalized Couplings, and Scale Invariance
Abstract
We present a comparative analysis of current observational constraints on three recently discussed alternative models for explaining the low-redshift acceleration of the universe: the so-called steady-state torsion model, the generalized coupling model, and the scale invariant model by Maeder (an example of a broader class which we also briefly study) These are compared to the traditional parameterization of Chevallier, Polarski and Linder. Each of the candidate models is studied under two different assumptions: as genuine alternatives to CDM (where a new degree of freedom would be expected to explain the recent acceleration of the universe without any cosmological constant) and as parametric extensions of CDM (where both a cosmological constant and the new mechanism can coexist, and the relative contributions of both are determined by the data). Our comparative analysis suggests that, from a phenomenological point of view, all such models neatly divide into two classes, with different observational consequences.
Cite
@article{arxiv.2111.08086,
title = {Alternatives to $\Lambda$: Torsion, Generalized Couplings, and Scale Invariance},
author = {C. J. A. P. Martins and C. M. J. Marques and C. B. D. Fernandes and J. S. J. S. Oliveira and D. A. R. Pinheiro and B. A. R. Rocha},
journal= {arXiv preprint arXiv:2111.08086},
year = {2021}
}
Comments
Summary of a talk given at the Theories of Gravity: Alternatives to the Cosmological and Particle Standard Models parallel session of the Sixteenth Marcel Grossmann Meeting, partially summarizing work previously reported in arXiv:1911.08232 and arXiv:2012.10513. To appear in the proceedings