An Attractive Proposal for Resolving the Hubble Tension: Dynamical Attractors that Unify Early and Late Dark Energy
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arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2023
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| _version_ | 1866913253976702976 |
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| author | Ramadan, Omar F. Karwal, Tanvi Sakstein, Jeremy |
| author_facet | Ramadan, Omar F. Karwal, Tanvi Sakstein, Jeremy |
| contents | Early dark energy is a promising potential resolution of the Hubble tension. Unfortunately, many models suffer from the need to fine-tune their initial conditions to ensure that the epoch of early dark energy coincides with matter-radiation equality. We propose a class of attractive early dark energy models where this coincidence arises naturally as a saddle point of a dynamical system that attracts a large volume of phase-space trajectories regardless of the initial conditions. The system approaches a global dark energy attractor at late-times. Our framework therefore unifies early and late dark energy using a single scalar degree of freedom. We analyze a fiducial attractive early dark energy model and find that it is disfavored by cosmological data due to the presence of a long-lived saddle point in the matter era where the scalar plays the role of an additional component of (non-clustering) dark matter. Our investigations provide lessons for future model-building efforts aimed at constructing viable attractive early dark energy models. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2309_08082 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | An Attractive Proposal for Resolving the Hubble Tension: Dynamical Attractors that Unify Early and Late Dark Energy Ramadan, Omar F. Karwal, Tanvi Sakstein, Jeremy Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Theory Early dark energy is a promising potential resolution of the Hubble tension. Unfortunately, many models suffer from the need to fine-tune their initial conditions to ensure that the epoch of early dark energy coincides with matter-radiation equality. We propose a class of attractive early dark energy models where this coincidence arises naturally as a saddle point of a dynamical system that attracts a large volume of phase-space trajectories regardless of the initial conditions. The system approaches a global dark energy attractor at late-times. Our framework therefore unifies early and late dark energy using a single scalar degree of freedom. We analyze a fiducial attractive early dark energy model and find that it is disfavored by cosmological data due to the presence of a long-lived saddle point in the matter era where the scalar plays the role of an additional component of (non-clustering) dark matter. Our investigations provide lessons for future model-building efforts aimed at constructing viable attractive early dark energy models. |
| title | An Attractive Proposal for Resolving the Hubble Tension: Dynamical Attractors that Unify Early and Late Dark Energy |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Theory |
| url | https://arxiv.org/abs/2309.08082 |