AI 中文总结
研究早期与晚期宇宙测量差异下，熵广义查普利金气体宇宙学对参数简并性的影响。通过多种数据约束模型，发现其能再现ΛCDM背景膨胀并改变参数区域，减少背景驱动差异，支持$H_0$和$S_8$张力源于不同物理扇区的可能性。
AI 中文摘要
早期和晚期宇宙测量之间持续存在的差异使宇宙学张力成为标准ΛCDM模型的主要检验。我们研究了描述统一暗区的熵广义查普利金气体宇宙学是否能改变与这些张力相关的参数简并性。利用来自PantheonPlus+SH0ES和DES--Dovekie的Ia型超新星数据、DESI BAO测量、RSD增长数据、压缩的普朗克2018距离先验以及普朗克透镜振幅先验对该模型进行了约束。我们发现熵gCg模型紧密再现了ΛCDM背景膨胀，同时引入了对距离-红移关系的可控晚期变形。这改变了偏好的$(H_0,\Omega_m,S_8)$区域，并部分减少了由背景驱动的差异，特别是那些涉及$H_0$的差异。使用\texttt{Tensiometer}量化共同导出参数空间$(H_0,\Omega_m,S_8)$中的后验偏移，我们表明相对于ΛCDM的位移主要沿对背景敏感的方向发生。因此，该模型比增长扇区更有效地修改了晚期膨胀扇区，使残余的$S_8$差异相对稳健。这些结果支持了$H_0$和$S_8$张力源于不同物理扇区的可能性。
英文摘要
Persistent discrepancies between early- and late-Universe measurements have made cosmological tensions a major test of the standard $Λ$CDM model. We investigate whether an entropic generalized Chaplygin-gas cosmology, describing a unified dark sector, can modify the parameter degeneracies associated with these tensions. The model is constrained using Type Ia supernova data from PantheonPlus+SH0ES and DES--Dovekie, DESI BAO measurements, RSD growth data, compressed Planck 2018 distance priors, and a Planck lensing-amplitude prior. We find that the entropic gCg model closely reproduces the $Λ$CDM background expansion while introducing a controlled late-time deformation of the distance--redshift relation. This shifts the preferred $(H_0,Ω_m,S_8)$ region and partially reduces background-driven discrepancies, especially those involving $H_0$. Using \texttt{Tensiometer} to quantify posterior shifts in the common derived parameter space $(H_0,Ω_m,S_8)$, we show that the displacement relative to $Λ$CDM occurs mainly along background-sensitive directions. The model therefore modifies the late-time expansion sector more effectively than the growth sector, leaving residual $S_8$ discrepancies comparatively robust. These results support the possibility that the $H_0$ and $S_8$ tensions arise from distinct physical sectors.
Comments20 pages, 9 figures
