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| Main Authors: | , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2502.19239 |
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| _version_ | 1866915173961302016 |
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| author | Soriano, Jorge F. Wohlberg, Shimon Anchordoqui, Luis A. |
| author_facet | Soriano, Jorge F. Wohlberg, Shimon Anchordoqui, Luis A. |
| contents | The proposal for a sudden sign-switching cosmological constant $Λ$ in the local universe, emulating a phase transition from anti-de Sitter (AdS) to de Sitter (dS) space, has markedly revamped the fit to observational data and lays out a propitious framework for ameliorating major cosmological tensions, such as the $H_0$ and $S_8$ tensions. This proposal is widely known as $Λ_s$CDM. We investigate the possibility that $Λ$ does not only flip sign at the transition but has also different curvature radii in the AdS and dS phases. We show that the critical redshift of the transition $z_c$ is strongly correlated with the vacuum energy in the AdS phase $Ω_{Λ_-}$, and that these two variables do not correlate strongly with the other cosmological parameters. We also show that the cost of adding an additional parameter to the $Λ_s$CDM cosmological model does not improve the goodness of fit. Armed with our findings, we demonstrate that for a proper choice of $z_c$, the vacuum energy in the dS phase may not necessarily be $-Ω_{Λ_-}$, for comparable degree of conformity between the model prediction and experimental data. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2502_19239 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | New insights on a sign-switching $Λ$ Soriano, Jorge F. Wohlberg, Shimon Anchordoqui, Luis A. Cosmology and Nongalactic Astrophysics The proposal for a sudden sign-switching cosmological constant $Λ$ in the local universe, emulating a phase transition from anti-de Sitter (AdS) to de Sitter (dS) space, has markedly revamped the fit to observational data and lays out a propitious framework for ameliorating major cosmological tensions, such as the $H_0$ and $S_8$ tensions. This proposal is widely known as $Λ_s$CDM. We investigate the possibility that $Λ$ does not only flip sign at the transition but has also different curvature radii in the AdS and dS phases. We show that the critical redshift of the transition $z_c$ is strongly correlated with the vacuum energy in the AdS phase $Ω_{Λ_-}$, and that these two variables do not correlate strongly with the other cosmological parameters. We also show that the cost of adding an additional parameter to the $Λ_s$CDM cosmological model does not improve the goodness of fit. Armed with our findings, we demonstrate that for a proper choice of $z_c$, the vacuum energy in the dS phase may not necessarily be $-Ω_{Λ_-}$, for comparable degree of conformity between the model prediction and experimental data. |
| title | New insights on a sign-switching $Λ$ |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2502.19239 |