Cosmological tests of chameleon dark energy with dark sector coupling
Abstract
Recent DESI measurements of baryon acoustic oscillations favor a value of Ωm different from that preferred by Planck cosmic microwave background observations. Combined with supernova data, these observations suggest an evolving dark energy equation of state that crosses w=−1. As a potential solution to multiple cosmological problems, chameleon dark energy has attracted increasing attention in recent years. In this work, we constrain a chameleon model in which late-time cosmic acceleration is driven by a canonical scalar field nonminimally coupled to dark matter. At early times, the scalar field evolves under the combined influence of its potential and the nonminimal coupling, and its effective mass greatly exceeds the Hubble parameter. The chameleon model with energy transfer from dark energy to dark matter yields a best-fit improvement of Δχ2=−7.25 relative to ΛCDM, comparable to that for energy transfer in the opposite direction. Joint sampling over both coupling directions favors a nonzero interaction at 3.3σ. Although no phantom field is introduced, the modified dark matter evolution produces an effective dark energy equation of state that crosses w=−1 at z≃0.5.
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BibTeX
@misc{wang2026cosmological,
title = {{Cosmological tests of chameleon dark energy with dark sector coupling}},
author = {Jia-Qi Wang and Zong-Kuan Guo and Shao-Jiang Wang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.40347},
eprint = {2610.40347},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.40347},
}
RIS
TY - UNPB
TI - Cosmological tests of chameleon dark energy with dark sector coupling
AU - Jia-Qi Wang
AU - Zong-Kuan Guo
AU - Shao-Jiang Wang
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.40347
UR - https://arxiv.org/abs/2610.40347
AB - Recent DESI measurements of baryon acoustic oscillations favor a value of Ω_m different from that preferred by Planck cosmic microwave background observations. Combined with supernova data, these observations suggest an evolving dark energy equation of state that crosses w=−1. As a potential solution to multiple cosmological problems, chameleon dark energy has attracted increasing attention in recent years. In this work, we constrain a chameleon model in which late-time cosmic acceleration is driven by a canonical scalar field nonminimally coupled to dark matter. At early times, the scalar field evolves under the combined influence of its potential and the nonminimal coupling, and its effective mass greatly exceeds the Hubble parameter. The chameleon model with energy transfer from dark energy to dark matter yields a best-fit improvement of Δχ^2=−7.25 relative to ΛCDM, comparable to that for energy transfer in the opposite direction. Joint sampling over both coupling directions favors a nonzero interaction at 3.3σ. Although no phantom field is introduced, the modified dark matter evolution produces an effective dark energy equation of state that crosses w=−1 at z≃0.5.
ER -