Time-dependent $G$ in Einstein's equations as an alternative to the cosmological constant
| Autor: | Isaac Tutusaus, Ekim Taylan Hanımeli, Brahim Lamine, Alain Blanchard |
|---|---|
| Přispěvatelé: | Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Riemann curvature tensor
data analysis method cosmological model Cosmology and Nongalactic Astrophysics (astro-ph.CO) General relativity gravitation: model FOS: Physical sciences General Relativity and Quantum Cosmology (gr-qc) Cosmological constant baryon: oscillation: acoustic 01 natural sciences General Relativity and Quantum Cosmology Metric expansion of space Tensor field symbols.namesake fundamental constant: time dependence statistical analysis 0103 physical sciences supernova general relativity energy: density 010306 general physics radiation: energy Scale factor (cosmology) Mathematical physics Physics Bianchi identity cosmological constant 010308 nuclear & particles physics field equations Cosmology Gravitational constant space-time field theory: tensor symbols [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc] gravitation: fundamental constant Baryon acoustic oscillations Einstein equation expansion: acceleration [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] Astrophysics - Cosmology and Nongalactic Astrophysics energy: conservation law |
| Zdroj: | Phys.Rev.D Phys.Rev.D, 2020, 101 (6), pp.063513. ⟨10.1103/PhysRevD.101.063513⟩ Digital.CSIC. Repositorio Institucional del CSIC instname Physical Review D Physical Review D, American Physical Society, 2020, 101 (6), pp.063513. ⟨10.1103/PhysRevD.101.063513⟩ |
| ISSN: | 1550-7998 1550-2368 |
| DOI: | 10.1103/PhysRevD.101.063513⟩ |
| Popis: | In this work, we investigate cosmologies where the gravitational constant varies in time, with the aim of explaining the accelerated expansion without a cosmological constant. We achieve this by considering a phenomenological extension to general relativity, modifying Einstein's field equations such that $G$ is a function of time, $G(t)$, and we preserve the geometrical consistency (Bianchi identity) together with the usual conservation of energy by introducing a new tensor field to the equations. In order to have concrete expressions to compare with cosmological data, we posit additional properties to this tensor field, in a way that it can be interpreted as a response of spacetime to a variation of $G$. Namely, we require that the energy this tensor represents is nonzero only when there is a time variation of $G$, and its energy depends on the scale factor only because of its coupling to $G$ and the matter and radiation energy densities. Focusing on the accelerated expansion period, we use type Ia supernovae and baryon acoustic oscillation data to determine the best fit of the cosmological parameters as well as the required variation in the gravitational constant. As a result, we find that it is possible to explain the accelerated expansion of the Universe with a variation of $G$ and no cosmological constant. The obtained variation of $G$ stays under 10 \% of its current value in the investigated redshift range and it is consistent with the local observations of $\dot{G}/G$. 9 pages, 2 figures, Phys. Rev. D Published in 12 March 2020 - https://link.aps.org/doi/10.1103/PhysRevD.101.063513 |
| Databáze: | OpenAIRE |
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