Cosmological perturbations for smooth sign-switching dark energy models
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arXiv
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| Format: | Preprint |
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2025
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| _version_ | 1866918158125760512 |
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| author | Bouhmadi-López, Mariam Ibarra-Uriondo, Beñat |
| author_facet | Bouhmadi-López, Mariam Ibarra-Uriondo, Beñat |
| contents | In this work, we carry out a comprehensive perturbative analysis of four cosmological models featuring a sign-switching cosmological constant. Among these, we include the well-known $Λ_{\rm s}$CDM model, characterised by an abrupt transition from a negative to a positive cosmological constant. We also consider the L$Λ$CDM model, which exhibits a generalised ladder-step evolution, as well as the SSCDM and ECDM models, both of which undergo a smooth sign change at comparable redshifts. We solve the linear cosmological perturbation equations from the radiation-dominated era, imposing initial adiabatic conditions for matter and radiation, for modes well outside the Hubble radius in the early Universe. We analyse the behaviour of the matter density contrast, the gravitational potential, the linear growth rate, the matter power spectrum, and the $fσ_8$ evolution . These results are contrasted with predictions from the standard $Λ$CDM model and are confronted with observational data. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2506_18992 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Cosmological perturbations for smooth sign-switching dark energy models Bouhmadi-López, Mariam Ibarra-Uriondo, Beñat General Relativity and Quantum Cosmology Cosmology and Nongalactic Astrophysics High Energy Physics - Phenomenology High Energy Physics - Theory In this work, we carry out a comprehensive perturbative analysis of four cosmological models featuring a sign-switching cosmological constant. Among these, we include the well-known $Λ_{\rm s}$CDM model, characterised by an abrupt transition from a negative to a positive cosmological constant. We also consider the L$Λ$CDM model, which exhibits a generalised ladder-step evolution, as well as the SSCDM and ECDM models, both of which undergo a smooth sign change at comparable redshifts. We solve the linear cosmological perturbation equations from the radiation-dominated era, imposing initial adiabatic conditions for matter and radiation, for modes well outside the Hubble radius in the early Universe. We analyse the behaviour of the matter density contrast, the gravitational potential, the linear growth rate, the matter power spectrum, and the $fσ_8$ evolution . These results are contrasted with predictions from the standard $Λ$CDM model and are confronted with observational data. |
| title | Cosmological perturbations for smooth sign-switching dark energy models |
| topic | General Relativity and Quantum Cosmology Cosmology and Nongalactic Astrophysics High Energy Physics - Phenomenology High Energy Physics - Theory |
| url | https://arxiv.org/abs/2506.18992 |