Constraints on the speed of sound in the k-essence model of dark energy
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| Format: | Preprint |
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2023
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| _version_ | 1866916132604084224 |
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| author | Dinda, Bikash R. Banerjee, Narayan |
| author_facet | Dinda, Bikash R. Banerjee, Narayan |
| contents | We consider a particular k-essence scalar field model for the late-time cosmic acceleration in which the sound speed, parametrized as $c_s$ is constant. We compute the relevant background and perturbation quantities corresponding to the observables like cosmic microwave background, type Ia supernova, cosmic chronometers, baryon acoustic oscillations, and the $fσ_8$. We put constraints on the $c_s^2$ parameter from these observations along with other parameters. We find lower values of $c_s^2$ which are close to zero are tightly constrained. Particularly, we find mean value of $\log_{\rm 10} (c_s^2)$ to be $-0.61$ and $c_s^2 \leq 10^{-3}$ is more than 3$σ$ away from this mean value. This means these observations favor a homogeneous dark energy component compared to the clustering one. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2309_10538 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Constraints on the speed of sound in the k-essence model of dark energy Dinda, Bikash R. Banerjee, Narayan Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology We consider a particular k-essence scalar field model for the late-time cosmic acceleration in which the sound speed, parametrized as $c_s$ is constant. We compute the relevant background and perturbation quantities corresponding to the observables like cosmic microwave background, type Ia supernova, cosmic chronometers, baryon acoustic oscillations, and the $fσ_8$. We put constraints on the $c_s^2$ parameter from these observations along with other parameters. We find lower values of $c_s^2$ which are close to zero are tightly constrained. Particularly, we find mean value of $\log_{\rm 10} (c_s^2)$ to be $-0.61$ and $c_s^2 \leq 10^{-3}$ is more than 3$σ$ away from this mean value. This means these observations favor a homogeneous dark energy component compared to the clustering one. |
| title | Constraints on the speed of sound in the k-essence model of dark energy |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2309.10538 |