Double the axions, half the tension: multi-field early dark energy eases the Hubble tension

2026/04/15 by Marco Bella, Vivian Poulin, Sunny Vagnozzi +1 · 1 voice
Physics and Astronomy · #astro-ph.CO #gr-qc #hep-ph

paper · pdf

Abstract

We show that the strong constraints placed by Planck NPIPE Cosmic Microwave Background (CMB) data on axion-like early dark energy (EDE) are significantly alleviated in models with multiple fields. We find a 1.5σ residual tension with the Local Distance Network value of H₀ in a 2-field model, with no improvement beyond two fields, and a best-fit value of H₀ ∼ 1.4σ larger than in the 1-field case. The second field improves the fit to high-ℓ CMB data, where 1-field EDE is most strongly disfavored, and suggests modifications to the pre-recombination history over a wider redshift range.

Citations

• The Atacama Cosmology Telescope

Discussions

• In cosmology, it’s said that when you have a problem, you add a scalar field to your model. And when that still doesn’t work? add another one! Fun and cool work led by talented undergrad student Marco [bsky, 1 points, 0 comments]

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