New Early Dark Energy introduces a new phase of dark energy that decays in a fast-triggered phase transition around matter-radiation equality. The presence of a trigger mechanism sets it apart from other early dark energy models. Here, we will argue that New Early Dark Energy offers a simple and natural framework to extend ΛCDM while also providing a pathway to resolving the H0 tension alongside its smaller cousin, the S8 tension. At the microscopic level, we discuss the possibility that the trigger is either given by an ultralight scalar field or a dark sector temperature. In both cases, it prompts the transition of an eV-mass scalar field from its false to its true minimum. Furthermore, we argue that the same phase transition could give rise to a dynamic process for generating neutrino masses.
@article{arxiv.2307.03481,
title = {New Early Dark Energy as a solution to the $H_0$ and $S_8$ tensions},
author = {Florian Niedermann and Martin S. Sloth},
journal= {arXiv preprint arXiv:2307.03481},
year = {2024}
}
Comments
Invited chapter for the edited book Hubble Constant Tension (Eds. E. Di Valentino and D. Brout, Springer Singapore, expected in 2024)