Rock ‘n’ roll solutions to the Hubble tension
By P. Agrawal, F. Cyr-Racine, D. Pinner, L. Randall. Physics of the Dark Universe, 2019
145 citations recorded by the source corpus.
Local measurements of the Hubble parameter are increasingly in tension with the value inferred from a $\Lambda$CDM fit to the cosmic microwave background (CMB) data. In this paper, we construct scenarios in which evolving scalar fields significantly ease this tension by adding energy to the Universe around recombination in a narrow redshift window. We identify solutions of $V \propto \phi^{2 n}$ with simple asymptotic behavior, both oscillatory (rocking) and rolling. These are the first solutions of this kind in which the field evolution and fluctuations are consistently implemented using the equations of motion. Our findings differ qualitatively from those of the existing literature, which rely upon a coarse-grained fluid description. Combining CMB data with low-redshift measurements, the best fit model has $n=2$ and increases the allowed value of $H_0$ from 69.2 km/s/Mpc in $\Lambda$CDM to 72.3 km/s/Mpc at $2\sigma$. Future measurements of the late-time amplitude of matter fluctuations and of the reionization history could help distinguish these models from competing solutions.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/609e8a07479a517f0e97c792cf00c689cc1dde21
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Citations in the corpus
- The Ups and Downs of Early Dark Energy solutions to the Hubble tension: A review of models, hints and constraints circa 2023 (2023, methodology): “Model: The Rock ’n’ Roll Early Dark Energy model [82] (RnR EDE) refers to a rolling scalar field with a potential of the form”
- A buyer’s guide to the Hubble constant (2021, background): “Agrawal et al. (2019) have shown H0 ∼ 72 km s−1 Mpc−1 for a fraction ΩEDE ∼ 5% of the energy content and the onset of its decay at redshift zc ∼ 5000, for a range of potentials.”