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This content will become publicly available on March 1, 2026

Title: Thermocoupled early dark energy
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 ∼ 10 % at the onset of matter domination to ≪ 1 % 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  more » « less
Award ID(s):
2412361
PAR ID:
10611915
Author(s) / Creator(s):
;
Publisher / Repository:
American Physical Society
Date Published:
Journal Name:
Physical Review D
Volume:
111
Issue:
6
ISSN:
2470-0010
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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