AI 中文总结
本研究利用DESI DR2重子声学振荡等多类观测数据约束修正涌现暗能量模型，发现其与标准ΛCDM模型整体兼容，拟合效果略优但无明确证据支持，也未呈现幽灵穿越行为，无法显著缓解H₀和S₈张力。
AI 中文摘要
在本研究中，我们利用暗能量光谱仪（Dark Energy Spectroscopic Instrument，DESI）第二次数据发布（DR2）的重子声学振荡测量结果，结合基于最新Planck NPIPE PR4版本的LoLLiPoP（低ℓ）和HiLLiPoP（高ℓ）似然值提供的宇宙微波背景（CMB）信息、Planck PR4引力透镜数据、ACT DR6引力透镜数据，以及三个Ia型超新星样本（Pantheon+、DES-Dovekie和Union3），对修正涌现暗能量（modified emergent dark energy，MEDE）模型展开研究。我们发现，MEDE模型与标准ΛCDM宇宙学模型在很大程度上保持一致。尽管模型允许与ΛCDM存在微小偏差，但加入Ia型超新星（SNe Ia）数据后，模型参数会向标准宇宙学场景收敛，其中参数α在1σ水平上与α=0保持一致。该模型无法显著缓解H₀或S₈张力：推断得到的H₀值仍低于SH0ES的测量结果，声学视界r_d几乎没有变化，预测的S₈值仍与ΛCDM模型的结果接近。重建的宇宙演化过程与ΛCDM的预测高度吻合，偏差通常低于0.5σ水平。虽然CMB+DESI DR2数据集更支持完全幽灵场（phantom）区域，但加入SNe Ia数据后，演化过程会向完全精质（quintessence）区域偏移。最后，尽管Δχ²_MAP和ΔAIC准则表明该模型的拟合效果略优于ΛCDM，但对数贝叶斯因子仅能提供支持MEDE模型的非决定性证据。总体而言，MEDE模型仍与当前观测结果兼容，但并未表现出近期DESI DR2分析所提出的幽灵穿越行为。
英文摘要
In this work, we investigate the modified emergent dark energy (MEDE) model using baryon acoustic oscillation measurements from the Dark Energy Spectroscopic Instrument Data Release 2 (DESI DR2), together with CMB information from the {\tt LoLLiPoP} (low-$\ell$) and {\tt HiLLiPoP} (high-$\ell$) likelihoods based on the latest Planck NPIPE PR4 release, Planck PR4 lensing, ACT DR6 lensing, and three Type Ia supernova samples (Pantheon$+$, DES-Dovekie, and Union3). We find that the MEDE model remains largely consistent with the standard $Λ$CDM cosmology. Although small departures from $Λ$CDM are allowed, the inclusion of SNe~Ia data drives the model parameters toward the standard cosmological scenario, with the parameter $α$ remaining consistent with $α=0$ at the $1σ$ level. The model does not significantly alleviate the $H_0$ or $S_8$ tensions: the inferred $H_0$ values remain below the SH0ES measurement, the sound horizon $r_d$ is nearly unchanged, and the predicted $S_8$ values remain close to those of $Λ$CDM. The reconstructed cosmological evolution closely follows the $Λ$CDM prediction, with deviations generally below the $0.5σ$ level. While the CMB + DESI DR2 dataset favors a full phantom regime, the inclusion of SNe~Ia shifts the evolution toward a full quintessence regime. Finally, although the $Δχ^2_{\rm MAP}$ and $Δ{\rm AIC}$ criteria indicate a marginally better fit than $Λ$CDM, the logarithmic Bayes factor provides only inconclusive evidence in favor of the MEDE model. Overall, the MEDE model remains compatible with current observations but does not exhibit the phantom-crossing behavior suggested by recent DESI DR2 analyses.
Comments13 pages, 6 figures, Published in Journal of High Energy Astrophysics (JHEAp)
Journal refJ. High Energy Astrophys. 55 (2027) 100716
DOI：10.1016/j.jheap.2026.100716
