Dynamical Dark Sector: A Joint Two-Scalar-Field Model for Dark Matter and Quintessence

Advances in Astronomy

卷:2026

Research Article

Silvio A. Corrêa Junior¹ 

[1] Engineering Institute, Universidade Santa Cecília, Santos, São Paulo, Brazil, unisanta.br

关键词: dark energy;    fuzzy dark matter;    modified CLASS code;    quintessence;    S tension;   

DOI  :  10.1155/aa/1708257

 received in 2025-12-30, accepted in 2026-06-30,  发布年份 2026

来源: Hindawi Publishing Corporation

【 摘 要 】

The physical nature of dark matter and dark energy remains one of the most pressing questions in modern cosmology. This work presents a phenomenological model where the entire dark sector is described by two minimally coupled scalar fields within general relativity. The first, an ultra-light scalar field Ψ with mass mΨ, constitutes Fuzzy Dark Matter (FDM), whose coherent oscillations dynamically replicate cold dark matter on large scales. The second, a quintessence field ϕ, evolves under an axion-like potential and serves as the dark energy component. We demonstrate that this framework can successfully reproduce the canonical cosmic history while offering a physical mechanism to address the S8 tension. By exploring the model’s parameter space, we show that the suppression of small-scale structure is a direct function of the FDM mass. For a benchmark mass of mΨ = 10−22 eV, chosen to illustrate the potential impact, we show that the model can produce a value of S8≡σ8Ωm/0.3 0.5 of approximately 0.79, illustrating a possible mechanism for reducing the tension between early and late-universe probes. Concurrently, the model predicts a “thawing” behavior for dark energy, with a present-day equation of state, wϕ,0, that depends on the potential’s parameters, yielding wϕ,0 ≈ −0.92 in our benchmark case. We acknowledge that the FDM mass required to affect the S8 tension creates a testable conflict with some Lyman-α forest constraints, a point we discuss as a key feature for the model’s falsifiability. By connecting cosmic acceleration, dark matter, and the S8 tension, this self-consistent framework offers a compelling and highly testable alternative to the ΛCDM model, motivating a full statistical analysis.

【 授权许可】

CC BY   
Copyright © 2026 Silvio A. Corrêa Junior. Advances in Astronomy published by John Wiley & Sons Ltd. 2026

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