Cosmographic analysis of sign-switching dark energy
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arXiv
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| Hauptverfasser: | , |
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| Format: | Preprint |
| Veröffentlicht: |
2025
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| _version_ | 1866911142254739456 |
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| author | Bouhmadi-López, Mariam Ibarra-Uriondo, Beñat |
| author_facet | Bouhmadi-López, Mariam Ibarra-Uriondo, Beñat |
| contents | Inspired by the well-studied $Λ_{\rm s}$CDM model, we propose and investigate a class of dynamical dark energy models that evolve from a negative cosmological constant, transitioning to a positive value at low redshifts. Specifically, we introduce a dark energy framework based on a generalised ladder-step function for the cosmological constant. Furthermore, we present two additional models in which the cosmological constant undergoes a smooth sign change at a specified redshift. We provide a detailed discussion of the construction and theoretical properties of these models, analysing their background cosmological evolution using a cosmographic approach and the statefinder hierarchy parameters. Our results are compared with those obtained for the standard $Λ$CDM and $Λ_{\rm s}$CDM models. We also perform a careful analysis of the types of singularities that may arise in these models due to a sign change in the cosmological constant. Notably, we show that a continuous sign change removes the sudden singularity present in the $Λ_{\rm s}$CDM model, replacing it with a milder $w$-singularity. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_12139 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Cosmographic analysis of sign-switching dark energy Bouhmadi-López, Mariam Ibarra-Uriondo, Beñat General Relativity and Quantum Cosmology Cosmology and Nongalactic Astrophysics High Energy Physics - Phenomenology High Energy Physics - Theory Inspired by the well-studied $Λ_{\rm s}$CDM model, we propose and investigate a class of dynamical dark energy models that evolve from a negative cosmological constant, transitioning to a positive value at low redshifts. Specifically, we introduce a dark energy framework based on a generalised ladder-step function for the cosmological constant. Furthermore, we present two additional models in which the cosmological constant undergoes a smooth sign change at a specified redshift. We provide a detailed discussion of the construction and theoretical properties of these models, analysing their background cosmological evolution using a cosmographic approach and the statefinder hierarchy parameters. Our results are compared with those obtained for the standard $Λ$CDM and $Λ_{\rm s}$CDM models. We also perform a careful analysis of the types of singularities that may arise in these models due to a sign change in the cosmological constant. Notably, we show that a continuous sign change removes the sudden singularity present in the $Λ_{\rm s}$CDM model, replacing it with a milder $w$-singularity. |
| title | Cosmographic analysis of sign-switching dark energy |
| topic | General Relativity and Quantum Cosmology Cosmology and Nongalactic Astrophysics High Energy Physics - Phenomenology High Energy Physics - Theory |
| url | https://arxiv.org/abs/2506.12139 |