Bulk viscous matter in $f(T)$ gravity: A path to cosmic acceleration
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| Format: | Preprint |
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2025
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| author | Myrzakulov, Kairat Donmez, O. Koussour, M. Muminov, S. Davletov, E. Rayimbaev, J. |
| author_facet | Myrzakulov, Kairat Donmez, O. Koussour, M. Muminov, S. Davletov, E. Rayimbaev, J. |
| contents | In this paper, we investigate the effects of varying bulk viscosity coefficients $ζ(t)=ζ_{0}+ζ_{1}H$ on cosmic evolution within the framework of $f(T)$ teleparallel gravity. We focus on two cases: (i) $ζ_{1} \neq0$ and (ii) $ζ_{1} =0$, deriving the Hubble parameter $H$ as a function of redshift $z$ using a linear $f(T)$ model ($f(T) = αT$ where $α\neq 0$). Using the combined $H(z)+Pantheon^{+}+BAO$ dataset, we obtain observational constraints on model parameters. For Case I ($ζ_1 \neq 0$), best-fit values are $H_0=60.0^{+2.0}_{-1.9}$ km/s/Mpc, $α=1.01^{+0.10}_{-0.098}$, $ζ_0=40.1^{+1.9}_{-2.0}$, and $ζ_1=0.123^{+0.093}_{-0.088}$, while for Case II ($ζ_1 = 0$), they are $H_0=67.5^{+1.3}_{-1.3}$ km/s/Mpc, $α=0.94^{+0.14}_{-0.13}$, and $ζ_0=34.7^{+2.0}_{-2.0}$. The analysis reveals a transition in the deceleration parameter, indicating a shift from deceleration to acceleration of the universe's expansion, with present-day values of $q_{0} \approx -0.49$ and $q_{0} \approx -0.32$ for the respective cases. The jerk parameter $j(z)$ and effective EoS for the cosmic viscous fluid also support the cosmic acceleration, with trajectories aligning with the quintessence scenario. These findings underscore the potential of our $f(T)$ model dominated by bulk viscous matter in explaining cosmic acceleration. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2501_03388 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Bulk viscous matter in $f(T)$ gravity: A path to cosmic acceleration Myrzakulov, Kairat Donmez, O. Koussour, M. Muminov, S. Davletov, E. Rayimbaev, J. Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology In this paper, we investigate the effects of varying bulk viscosity coefficients $ζ(t)=ζ_{0}+ζ_{1}H$ on cosmic evolution within the framework of $f(T)$ teleparallel gravity. We focus on two cases: (i) $ζ_{1} \neq0$ and (ii) $ζ_{1} =0$, deriving the Hubble parameter $H$ as a function of redshift $z$ using a linear $f(T)$ model ($f(T) = αT$ where $α\neq 0$). Using the combined $H(z)+Pantheon^{+}+BAO$ dataset, we obtain observational constraints on model parameters. For Case I ($ζ_1 \neq 0$), best-fit values are $H_0=60.0^{+2.0}_{-1.9}$ km/s/Mpc, $α=1.01^{+0.10}_{-0.098}$, $ζ_0=40.1^{+1.9}_{-2.0}$, and $ζ_1=0.123^{+0.093}_{-0.088}$, while for Case II ($ζ_1 = 0$), they are $H_0=67.5^{+1.3}_{-1.3}$ km/s/Mpc, $α=0.94^{+0.14}_{-0.13}$, and $ζ_0=34.7^{+2.0}_{-2.0}$. The analysis reveals a transition in the deceleration parameter, indicating a shift from deceleration to acceleration of the universe's expansion, with present-day values of $q_{0} \approx -0.49$ and $q_{0} \approx -0.32$ for the respective cases. The jerk parameter $j(z)$ and effective EoS for the cosmic viscous fluid also support the cosmic acceleration, with trajectories aligning with the quintessence scenario. These findings underscore the potential of our $f(T)$ model dominated by bulk viscous matter in explaining cosmic acceleration. |
| title | Bulk viscous matter in $f(T)$ gravity: A path to cosmic acceleration |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2501.03388 |