Interacting dark energy: clarifying the cosmological implications and viability conditions
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arXiv
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| Autores principales: | , |
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| Formato: | Preprint |
| Publicado: |
2023
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| _version_ | 1866929216474316800 |
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| author | van der Westhuizen, Marcel A. Abebe, Amare |
| author_facet | van der Westhuizen, Marcel A. Abebe, Amare |
| contents | In this study, cosmological models are considered, where dark matter and dark energy are coupled and may exchange energy through non-gravitational interactions with one other. These interacting dark energy (IDE) models have previously been introduced to address problems with the standard $Λ$CDM model of cosmology (which include the coincidence problem, Hubble tension and $S_8$ discrepancy). However, conditions ensuring positive energy densities have often been overlooked. Assuming two different linear dark energy couplings, $Q = δH ρ_{\rm{de}}$ and $Q = δH ρ_{\rm{dm}}$, we find that negative energy densities are inevitable if energy flows from dark matter to dark energy (iDMDE regime) and that consequently, we should only seriously consider models where energy flows from dark energy to dark matter (iDEDM regime). To additionally ensure that these models are free from early time instabilities, we need to require that dark energy is in the `phantom' ($ω<-1$) regime. This has the consequence that model $Q=δH ρ_{\rm{dm}}$ will end with a future big rip singularity, while $Q = δH ρ_{\rm{de}}$ may avoid this fate with the right choice of cosmological parameters. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2302_11949 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Interacting dark energy: clarifying the cosmological implications and viability conditions van der Westhuizen, Marcel A. Abebe, Amare General Relativity and Quantum Cosmology Cosmology and Nongalactic Astrophysics In this study, cosmological models are considered, where dark matter and dark energy are coupled and may exchange energy through non-gravitational interactions with one other. These interacting dark energy (IDE) models have previously been introduced to address problems with the standard $Λ$CDM model of cosmology (which include the coincidence problem, Hubble tension and $S_8$ discrepancy). However, conditions ensuring positive energy densities have often been overlooked. Assuming two different linear dark energy couplings, $Q = δH ρ_{\rm{de}}$ and $Q = δH ρ_{\rm{dm}}$, we find that negative energy densities are inevitable if energy flows from dark matter to dark energy (iDMDE regime) and that consequently, we should only seriously consider models where energy flows from dark energy to dark matter (iDEDM regime). To additionally ensure that these models are free from early time instabilities, we need to require that dark energy is in the `phantom' ($ω<-1$) regime. This has the consequence that model $Q=δH ρ_{\rm{dm}}$ will end with a future big rip singularity, while $Q = δH ρ_{\rm{de}}$ may avoid this fate with the right choice of cosmological parameters. |
| title | Interacting dark energy: clarifying the cosmological implications and viability conditions |
| topic | General Relativity and Quantum Cosmology Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2302.11949 |