Scaling solutions as Early Dark Energy resolutions to the Hubble tension

Copeland, Edmund J.; Moss, Adam; Sevillano Muñoz, Sergio; White, Jade M.M.

Abstract

A wide class of scalar field models including Quintessence and K-essence have the attractive property of tracker regimes, where the energy density stored in the field evolves so as to mimic that of the dominant background component. During this evolution, for a brief period of time, there is an increase in the energy density of the field as it spirals in towards its attractor solution. We show that when the peak of this energy density occurs around the epoch of equality, we can address a key requirement of early dark energy (EDE), postulated as a solution to the Hubble tension. In particular we demonstrate how this can occur in a wide class of Quintessence, axion and K-essence models, before showing that the Quintessence models suffer in that they generally lead to sound speeds incompatible with the requirements of EDE, whereas the K-essence and axion models can do a better job of fitting the data.

Citation

Copeland, E. J., Moss, A., Sevillano Muñoz, S., & White, J. M. (2024). Scaling solutions as Early Dark Energy resolutions to the Hubble tension. Journal of Cosmology and Astroparticle Physics, 2024(05), Article 078. https://doi.org/10.1088/1475-7516/2024/05/078

• Journal Article Type: Article
• Acceptance Date: Apr 11, 2024
• Online Publication Date: May 14, 2024
• Publication Date: May 1, 2024
• Deposit Date: May 20, 2024
• Publicly Available Date: May 20, 2024
• Journal: Journal of Cosmology and Astroparticle Physics
• Electronic ISSN: 1475-7516
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 2024
• Issue: 05
• Article Number: 078
• DOI: https://doi.org/10.1088/1475-7516/2024/05/078
• Keywords: CMBR theory, supernova type Ia - standard candles, dark energy theory
• Public URL: https://durham-repository.worktribe.com/output/2443580