超越动力学暗能量：DESI DR2之后暗 sector 相互作用的作用
Beyond dynamical dark energy: the role of dark sector interactions after DESI DR2
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中文总结 AI 辅助
该研究在 DESI DR2 观测背景下，探讨暗 sector 相互作用是否影响暗能量，结合多数据约束模型，发现暗 sector 相互作用的推断作用依赖于暗能量性质，贝叶斯比较仍偏好 $\rm \u039CDM$。
中文摘要 AI 辅助
近期 DESI DR2 观测重新激发了人们对 $\rm \u039CDM$ 宇宙学模型扩展的兴趣，尤其是通过时变暗能量状态方程的迹象。本研究探讨此类偏差是否也可能涉及暗 sector 内部的相互作用。我们考虑一种相互作用暗能量场景，其中暗物质密度演化满足 $\rho_{\rm dm}\u221da^{-3+\u03b4}$，常数 $\u03b4$ 量化相互作用强度，且允许暗能量状态方程为常数但不等于 -1，或通过 CPL 参数化动态演化。模型使用 Planck CMB 数据、DESI DR2 BAO 测量值以及三个 Ia 型超新星汇编（PantheonPlus、Union3 和 DES-Dovekie）进行约束。对于常数状态方程情况，纳入 DESI 和超新星数据导致偏好小的负相互作用参数，显著性高于 $2\u03c3$；当允许动态暗能量时，相互作用的证据变弱，而数据支持类 quintessence 的演化暗能量组分。在两种场景下，贝叶斯模型比较仍偏好 $\rm \u039CDM$。我们的结果表明，推断的暗 sector 相互作用的作用强烈依赖于暗能量的性质，凸显了在 DESI 时代联合检验暗能量动力学与相互作用的重要性。
英文摘要
Recent DESI DR2 observations have renewed interest in extensions of the $Λ$CDM cosmological model, particularly through indications of a time-varying dark energy equation of state. In this work, we investigate whether such deviations may also involve interactions within the dark sector. We consider an interacting dark energy scenario in which the dark matter density evolves as $ρ_{\rm dm}\propto a^{-3+δ}$, with the constant $δ$ quantifying the interaction strength, and allow the dark energy equation of state to be either constant but different from $-1$, or dynamically evolving through the CPL parametrization. The models are constrained using Planck CMB data, DESI DR2 BAO measurements, and three Type Ia supernova compilations: PantheonPlus, Union3, and DES-Dovekie. For the constant equation-of-state case, the inclusion of DESI and supernova data leads to a preference for a small negative interaction parameter, with a significance above $2σ$. When dynamical dark energy is allowed, the evidence for interaction becomes weak, while the data favor a quintessence-like evolving dark energy component. In both scenarios, Bayesian model comparison still favors $Λ$CDM. Our results show that the inferred role of dark-sector interactions depends strongly on the nature of dark energy, highlighting the importance of jointly testing dark energy dynamics and interactions in the DESI era.
