Beyond $Λ$CDM: Exploring a Dynamical Cosmological Constant Framework Consistent with Late-Time Observations
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| Format: | Preprint |
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2025
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| _version_ | 1866917041702699008 |
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| author | Dixit, Archana Yadav, Manish Pradhan, Anirudh Barak, M. S. |
| author_facet | Dixit, Archana Yadav, Manish Pradhan, Anirudh Barak, M. S. |
| contents | In this work, we investigate a cosmological scenario with a time-dependent cosmological constant $Λ$(t) within the spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) framework. Here we study a power-law $Λ(t)$CDM model characterized by a dynamic cosmological constant expressed as a function of the Hubble parameter and its derivative $Λ(t)$ $=α(\dot H+H^{2})+λH^2+4πGρη.$ Using recent observational datasets (DESI BAO, OHD, and PP\&SH0ES), we constrain the model's free parameters $(H_{0},α,λ,η)$ and analyze their impact on key cosmological quantities. A Markov chain Monte Carlo (MCMC) analysis of the best-fit value of $H_{0}=71.9\pm 0.23$ km/s/Mpc from PP\&SH0ES analysis only, which substantially alleviates the existing tension between early and late-time determinations of the Hubble constant, reducing it to $\sim1.5σ$. The reconstructed $Om$ diagnostic exhibits a negative slope, indicating a dynamic dark energy behavior with quintessence-like characteristics ($ω>-1$). These results suggest that the proposed $Λ(t)$ model provides a viable alternative to the standard $Λ$CDM paradigm to explain the late-time acceleration of the universe. Our findings show that this model alleviates the Hubble tension more effectively than the standard $Λ$CDM . The model also demonstrates compatibility with late-time Hubble parameter observations and offers a compelling framework to address the limitations of $Λ$CDM. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2510_21875 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Beyond $Λ$CDM: Exploring a Dynamical Cosmological Constant Framework Consistent with Late-Time Observations Dixit, Archana Yadav, Manish Pradhan, Anirudh Barak, M. S. General Relativity and Quantum Cosmology In this work, we investigate a cosmological scenario with a time-dependent cosmological constant $Λ$(t) within the spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) framework. Here we study a power-law $Λ(t)$CDM model characterized by a dynamic cosmological constant expressed as a function of the Hubble parameter and its derivative $Λ(t)$ $=α(\dot H+H^{2})+λH^2+4πGρη.$ Using recent observational datasets (DESI BAO, OHD, and PP\&SH0ES), we constrain the model's free parameters $(H_{0},α,λ,η)$ and analyze their impact on key cosmological quantities. A Markov chain Monte Carlo (MCMC) analysis of the best-fit value of $H_{0}=71.9\pm 0.23$ km/s/Mpc from PP\&SH0ES analysis only, which substantially alleviates the existing tension between early and late-time determinations of the Hubble constant, reducing it to $\sim1.5σ$. The reconstructed $Om$ diagnostic exhibits a negative slope, indicating a dynamic dark energy behavior with quintessence-like characteristics ($ω>-1$). These results suggest that the proposed $Λ(t)$ model provides a viable alternative to the standard $Λ$CDM paradigm to explain the late-time acceleration of the universe. Our findings show that this model alleviates the Hubble tension more effectively than the standard $Λ$CDM . The model also demonstrates compatibility with late-time Hubble parameter observations and offers a compelling framework to address the limitations of $Λ$CDM. |
| title | Beyond $Λ$CDM: Exploring a Dynamical Cosmological Constant Framework Consistent with Late-Time Observations |
| topic | General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2510.21875 |