Anisotropy screening in Horndeski cosmologies
| Autor: | Alexei A. Starobinsky, Sergey V. Sushkov, Mikhail S. Volkov |
|---|---|
| Přispěvatelé: | Fédération de recherche Denis Poisson (FDP), Université d'Orléans (UO)-Université de Tours-Centre National de la Recherche Scientifique (CNRS), Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO) |
| Rok vydání: | 2020 |
| Předmět: |
High Energy Physics - Theory
Bianchi media_common.quotation_subject Scalar (mathematics) FOS: Physical sciences alternative theories of gravity General Relativity and Quantum Cosmology (gr-qc) 01 natural sciences General Relativity and Quantum Cosmology photon: velocity symbols.namesake 0103 physical sciences Tensor initial state 010306 general physics Anisotropy media_common Mathematical physics Physics charge: scalar Spacetime [PHYS.HTHE]Physics [physics]/High Energy Physics - Theory [hep-th] 010308 nuclear & particles physics screening perturbation: tensor Charge (physics) stability 16. Peace & justice Coupling (probability) singularity Universe tensor: Einstein Einstein tensor High Energy Physics - Theory (hep-th) General relativity space-time: model gravitation cosmological model: anisotropy [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc] symbols |
| Zdroj: | Physical Review Physical Review D Physical Review D, American Physical Society, 2020, 101 (6), pp.064039. ⟨10.1103/PhysRevD.101.064039⟩ Phys.Rev.D Phys.Rev.D, 2020, 101 (6), pp.064039. ⟨10.1103/PhysRevD.101.064039⟩ |
| ISSN: | 2470-0029 2470-0010 1550-7998 1550-2368 |
| DOI: | 10.1103/physrevd.101.064039 |
| Popis: | We consider anisotropic cosmologies in a particular shift-symmetric Horndeski theory containing the $G^{\mu\nu}\partial_\mu\phi \partial_\nu\phi$ coupling, where $G^{\mu\nu}$ is the Einstein tensor. This theory admits stable in the future self-accelerating cosmologies whose tensor perturbations propagate with the velocity very close to the speed of light such that the theory agrees with the gravity wave observations. Surprisingly, we find that the anisotropies within the Bianchi I homogeneous spacetime model are screened at early time by the scalar charge, whereas at late times they are damped in the usual way. Therefore, contrary to what one would normally expect, the early state of the universe in the theory cannot be anisotropic and (locally) homogeneous in the absence of spatial curvature. The early universe cannot be isotropic either, because it should then be unstable with respect to inhomogeneous perturbations. As a result, the early universe should be inhomogeneous. At the same time, we find that in the spatially curved Bianchi IX case the anisotropies can be strong at early times even in the presence of a scalar charge. Comment: 18 pages, 2 figures, matches the published version |
| Databáze: | OpenAIRE |
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