Testing a varying-Λ model for dark energy within co-varying physical couplings framework
Abstract
The Co-varying Physical Couplings (CPC) framework is a modified gravity set up assuming Einstein Field Equations wherein the quantities {G, c, Λ} are promoted to space-time functions. Bianchi identity and the requirement of stress-energy tensor conservation entangle the possible variations of the couplings {G, c, Λ}, which are forced to co-vary as dictated by the General Constraint (GC). In this paper, we explore a cosmological model wherein G, c, and Λ are functions of the redshift respecting the GC of the CPC framework. We assume a linear parametrization of Λ in terms of the scale factor a. We use the ansatz $\dot{G}/G = \sigma \left(\dot{c}/c \right)$ with σ = constant to deduce the functional forms of c = c(z) and G = G(z). We show that this varying-{G, c, Λ} model fits SNe Ia data and H(z) data with σ = 3. The model parameters can be constrained to describe dark energy at the background level.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 2022
- DOI:
- 10.1093/mnras/stac2039
- arXiv:
- arXiv:2204.10764
- Bibcode:
- 2022MNRAS.515.5981C
- Keywords:
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- gravitation;
- cosmological parameters;
- cosmology: theory;
- dark energy;
- distance scale;
- General Relativity and Quantum Cosmology;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 14 pages plus references and figures