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Early dark energy solutions to the Hubble tension introduce an additional scalar field which is frozen at early times but becomes dynamical around matter-radiation equality. In order to alleviate the tension, the scalar’s share of the total energy density must rapidly shrink from at the onset of matter domination to by recombination. This typically requires a steep potential that is imposed rather than emerging from a concrete particle physics model. Here, we point out an alternative possibility: a homogeneous scalar field coupled quadratically to a cosmological background of light thermal relics (such as the Standard Model neutrino) will acquire an effective potential which can reproduce the dynamics necessary to alleviate the tension. We identify the relevant parameter space for this “thermocoupled” scenario and study its unique phenomenology at the background level, including the back-reaction on the neutrino mass. Follow-up numerical work is necessary to determine the constraints placed on the model by early time measurements. Published by the American Physical Society2025
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Cosmic Expansion: A mini review of the Hubble-Lemaitre tension
We present here a lightning review of the status of the Hubble-Lemaître tension. Instead of discussing the broad array of proposed solutions found in the literature, we focus here on the assumptions made to measure the Hubble constant from cosmic microwave background and baryon acoustic oscillation data on the one hand, and from a cepheid-calibrated distance ladder on the other hand. From this discussion, we extract two important lessons that inform which kind of physics-based solutions could plausibly resolve this tension.
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- Award ID(s):
- 2008696
- PAR ID:
- 10351495
- Editor(s):
- Etienne Auge, Jacques Dumarchez
- Date Published:
- Journal Name:
- 2021 Electroweak Interactions and Unified Theories, 55th Rencontres de Moriond
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.48550/arXiv.2105.09409
