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| Hauptverfasser: | , , , |
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| Format: | Preprint |
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2023
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| Online-Zugang: | https://arxiv.org/abs/2307.02602 |
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| _version_ | 1866912532573192192 |
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| author | Sengupta, Rikpratik Chanda, Anirban Paul, B C Kalam, M |
| author_facet | Sengupta, Rikpratik Chanda, Anirban Paul, B C Kalam, M |
| contents | In this paper, we attempt to explore the possibility of a obtaining a viable emergent universe scenario supported by a type of fluid known as the extended Chaplygin gas, which extends a modification to the equation of state of the well known modified Chaplygin gas by considering additional higher order barotropic fluid terms. We consider quadratic modification only. Such a fluid is capable of explaining the present cosmic acceleration and is a possible dark energy candidate. We construct a theoretical model of the emergent universe assuming it is dominated by such a fluid at late times. Our model results in non-conventional late-time behavior and deviates from the standard $Λ$-CDM model. Dark energy is found to cross the \textit{phantom} divide in the past and present besides exhibiting \textit{thawing} behaviour in the future, asymptotically leading to transition into a decelerating phase making dark energy a \textit{transient} phenomenon. The qualitative nature of variation of the cosmological parameters resulting from model parameters observationally constrained through Markov Chain Monte Carlo sampling of Pantheon+OHD data is interestingly found to resemble the DESI results. Also,the value of $H(z)$ at a redshift $z=2.34$ and present value of Hubble parameter fits much better than $Λ$-CDM with recent observations. This leads us to the realization that such a fluid is not only a probable candidate for dark energy, but also sources an emergent universe unlike modified Chaplygin gas and the initial singularity problem can be resolved in a flat universe within the standard relativistic context. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2307_02602 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Observationally constrained emergent universe scenario with non-conventional late-time dynamics Sengupta, Rikpratik Chanda, Anirban Paul, B C Kalam, M General Relativity and Quantum Cosmology In this paper, we attempt to explore the possibility of a obtaining a viable emergent universe scenario supported by a type of fluid known as the extended Chaplygin gas, which extends a modification to the equation of state of the well known modified Chaplygin gas by considering additional higher order barotropic fluid terms. We consider quadratic modification only. Such a fluid is capable of explaining the present cosmic acceleration and is a possible dark energy candidate. We construct a theoretical model of the emergent universe assuming it is dominated by such a fluid at late times. Our model results in non-conventional late-time behavior and deviates from the standard $Λ$-CDM model. Dark energy is found to cross the \textit{phantom} divide in the past and present besides exhibiting \textit{thawing} behaviour in the future, asymptotically leading to transition into a decelerating phase making dark energy a \textit{transient} phenomenon. The qualitative nature of variation of the cosmological parameters resulting from model parameters observationally constrained through Markov Chain Monte Carlo sampling of Pantheon+OHD data is interestingly found to resemble the DESI results. Also,the value of $H(z)$ at a redshift $z=2.34$ and present value of Hubble parameter fits much better than $Λ$-CDM with recent observations. This leads us to the realization that such a fluid is not only a probable candidate for dark energy, but also sources an emergent universe unlike modified Chaplygin gas and the initial singularity problem can be resolved in a flat universe within the standard relativistic context. |
| title | Observationally constrained emergent universe scenario with non-conventional late-time dynamics |
| topic | General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2307.02602 |