Scalar perturbations in f(T) gravity using the $$1 + 3$$ 1+3 covariant approach
Abstract The cosmological scalar perturbations of standard matter are investigated in the context of extended teleparallel f(T) gravity theories using the $$1+3$$ 1+3 covariant formalism. After a review of the background gravitational field equations of f(T) gravity and the introduction of the covar...
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| Format: | Article |
| Language: | English |
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SpringerOpen
2020-05-01
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| Series: | European Physical Journal C: Particles and Fields |
| Online Access: | http://link.springer.com/article/10.1140/epjc/s10052-020-7961-3 |
| _version_ | 1818412229772443648 |
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| author | Shambel Sahlu Joseph Ntahompagaze Amare Abebe Álvaro de la Cruz-Dombriz David F. Mota |
| author_facet | Shambel Sahlu Joseph Ntahompagaze Amare Abebe Álvaro de la Cruz-Dombriz David F. Mota |
| author_sort | Shambel Sahlu |
| collection | DOAJ |
| description | Abstract The cosmological scalar perturbations of standard matter are investigated in the context of extended teleparallel f(T) gravity theories using the $$1+3$$ 1+3 covariant formalism. After a review of the background gravitational field equations of f(T) gravity and the introduction of the covariant perturbation variables, the usual scalar and harmonic decomposition have been performed, and the analysis of the growth of the density contrasts in the quasi-static approximation for two non-interacting fluids scenarios, namely torsion-dust and torsion-radiation mixtures is presented for the generic f(T) gravity theory. Special applications to two classes of f(T) gravity toy models, namely $$f(T) = \mu T_0 \Big (\frac{T}{T_0}\Big )^n$$ f(T)=μT0(TT0)n and $$f(T) = T+ \mu T_0 \Big (-\frac{T}{T_0}\Big )^n$$ f(T)=T+μT0(-TT0)n , have then been made within the observationally viable regions of their respective parameter spaces, and the growth of the matter density contrast for both torsion-dust and torsion-radiation epochs of the Universe has been examined. The exact solutions of the dust perturbations, with growing amplitudes in cosmic time, are obtained for some limiting cases of n. Similarly, the long- and short-wavelength modes in the torsion-radiation case are treated, with the amplitudes either oscillating or monotonically growing with time. Overall, it is noted that f(T) models contain a richer set of observationally viable structure growth scenarios that can be tested against up-and-coming observational data and can accommodate currently known features of the large-scale structure power spectrum in the general relativistic and $$\varLambda CDM$$ ΛCDM limits. |
| first_indexed | 2024-12-14T10:44:00Z |
| format | Article |
| id | doaj.art-24040a8b86a846e088bddf98924997ee |
| institution | Directory Open Access Journal |
| issn | 1434-6044 1434-6052 |
| language | English |
| last_indexed | 2024-12-14T10:44:00Z |
| publishDate | 2020-05-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | European Physical Journal C: Particles and Fields |
| spelling | doaj.art-24040a8b86a846e088bddf98924997ee2022-12-21T23:05:32ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60441434-60522020-05-0180511910.1140/epjc/s10052-020-7961-3Scalar perturbations in f(T) gravity using the $$1 + 3$$ 1+3 covariant approachShambel Sahlu0Joseph Ntahompagaze1Amare Abebe2Álvaro de la Cruz-Dombriz3David F. Mota4Astronomy and Astrophysics Research and Development Department, Ethiopian Space Science and Technology InstituteAstronomy and Astrophysics Research and Development Department, Ethiopian Space Science and Technology InstituteCenter for Space Research, North-West UniversityCosmology and Gravity Group, Mathematics and Applied Mathematics, University of Cape TownInstitute of Theoretical Astrophysics, University of OsloAbstract The cosmological scalar perturbations of standard matter are investigated in the context of extended teleparallel f(T) gravity theories using the $$1+3$$ 1+3 covariant formalism. After a review of the background gravitational field equations of f(T) gravity and the introduction of the covariant perturbation variables, the usual scalar and harmonic decomposition have been performed, and the analysis of the growth of the density contrasts in the quasi-static approximation for two non-interacting fluids scenarios, namely torsion-dust and torsion-radiation mixtures is presented for the generic f(T) gravity theory. Special applications to two classes of f(T) gravity toy models, namely $$f(T) = \mu T_0 \Big (\frac{T}{T_0}\Big )^n$$ f(T)=μT0(TT0)n and $$f(T) = T+ \mu T_0 \Big (-\frac{T}{T_0}\Big )^n$$ f(T)=T+μT0(-TT0)n , have then been made within the observationally viable regions of their respective parameter spaces, and the growth of the matter density contrast for both torsion-dust and torsion-radiation epochs of the Universe has been examined. The exact solutions of the dust perturbations, with growing amplitudes in cosmic time, are obtained for some limiting cases of n. Similarly, the long- and short-wavelength modes in the torsion-radiation case are treated, with the amplitudes either oscillating or monotonically growing with time. Overall, it is noted that f(T) models contain a richer set of observationally viable structure growth scenarios that can be tested against up-and-coming observational data and can accommodate currently known features of the large-scale structure power spectrum in the general relativistic and $$\varLambda CDM$$ ΛCDM limits.http://link.springer.com/article/10.1140/epjc/s10052-020-7961-3 |
| spellingShingle | Shambel Sahlu Joseph Ntahompagaze Amare Abebe Álvaro de la Cruz-Dombriz David F. Mota Scalar perturbations in f(T) gravity using the $$1 + 3$$ 1+3 covariant approach European Physical Journal C: Particles and Fields |
| title | Scalar perturbations in f(T) gravity using the $$1 + 3$$ 1+3 covariant approach |
| title_full | Scalar perturbations in f(T) gravity using the $$1 + 3$$ 1+3 covariant approach |
| title_fullStr | Scalar perturbations in f(T) gravity using the $$1 + 3$$ 1+3 covariant approach |
| title_full_unstemmed | Scalar perturbations in f(T) gravity using the $$1 + 3$$ 1+3 covariant approach |
| title_short | Scalar perturbations in f(T) gravity using the $$1 + 3$$ 1+3 covariant approach |
| title_sort | scalar perturbations in f t gravity using the 1 3 1 3 covariant approach |
| url | http://link.springer.com/article/10.1140/epjc/s10052-020-7961-3 |
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