Dynamical dark energy from an ultralight axion

Fuente: arXiv
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Main Authors: Luu, Hoang Nhan, Qiu, Yu-Cheng, Tye, S. -H. Henry
Format: Preprint
Published: 2025
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author Luu, Hoang Nhan
Qiu, Yu-Cheng
Tye, S. -H. Henry
author_facet Luu, Hoang Nhan
Qiu, Yu-Cheng
Tye, S. -H. Henry
contents Recently the Dark Energy Survey (DES) Collaboration presented evidence that the equation of state $w$ of the dark energy is varying, or $w \simeq -0.948$ if it is constant. In either case, the dark energy cannot be due to a cosmological constant alone. Here we study an ultralight axion (or axion-like particle) with mass $m_ϕ\simeq 2 \times 10^{-33}$ eV that has properties that can explain the new $w$ measurement. In particular, $w\ge -1$ and a negative cosmological constant $Λ< 0$ is preferred in this model. We also present a simple formula for $w$ for the model to ease data fitting.
format Preprint
id arxiv_https___arxiv_org_abs_2503_18120
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dynamical dark energy from an ultralight axion
Luu, Hoang Nhan
Qiu, Yu-Cheng
Tye, S. -H. Henry
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
Recently the Dark Energy Survey (DES) Collaboration presented evidence that the equation of state $w$ of the dark energy is varying, or $w \simeq -0.948$ if it is constant. In either case, the dark energy cannot be due to a cosmological constant alone. Here we study an ultralight axion (or axion-like particle) with mass $m_ϕ\simeq 2 \times 10^{-33}$ eV that has properties that can explain the new $w$ measurement. In particular, $w\ge -1$ and a negative cosmological constant $Λ< 0$ is preferred in this model. We also present a simple formula for $w$ for the model to ease data fitting.
title Dynamical dark energy from an ultralight axion
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2503.18120