Testing a varying-Λ model for dark energy within co-varying physical couplings framework
| Autor: | R R Cuzinatto, R P Gupta, R F L Holanda, J F Jesus, S H Pereira |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Monthly Notices of the Royal Astronomical Society. 515:5981-5992 |
| ISSN: | 1365-2966 0035-8711 |
| DOI: | 10.1093/mnras/stac2039 |
| Popis: | The Co-varying Physical Couplings (CPC) framework is a modified gravity set up assuming Einstein Field Equations wherein the quantities $\{G,c,\Lambda\}$ are promoted to space-time functions. Bianchi identity and the requirement of stress-energy tensor conservation entangle the possible variations of the couplings $\{G,c,\Lambda\}$, 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 $\Lambda$ are functions of the redshift respecting the GC of the CPC framework. We assume a linear parametrization of $\Lambda$ in terms of the scale factor $a$. We use the ansatz $\dot{G}/G = \sigma \left( \dot{c}/c \right)$ with $\sigma =$ constant to deduce the functional forms of $c=c(z)$ and $G=G(z)$. We show that this varying-$\{G,c,\Lambda\}$ model fits SNe Ia data and $H(z)$ data with $\sigma = 3$. The model parameters can be constrained to describe dark energy at the background level. Comment: 14 pages plus references and figures; v2: matches the published version |
| Databáze: | OpenAIRE |
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