发表机构
The Institute for Fundamental Study “The Tah Poe Academia Institute”, Naresuan University; NAS, Centre for Theoretical Physics & Natural Philosophy, Mahidol University; Department of Physics, Naresuan University（那莱苏安大学基础研究院“塔波学术院”; 马希隆大学自然与科学研究中心理论物理与自然哲学中心; 那莱苏安大学物理系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究比较了由Kruglov非加性熵的两种热力学实现导出的宇宙学模型，发现模型I被观测数据强烈否定，而模型II接近标准宇宙学，表明熵纳入方式对宇宙学模型可行性至关重要。
AI 中文摘要
我们研究了由Kruglov非加性熵在表观视界处产生的两个晚期宇宙学模型。模型I最初由Kruglov推导，遵循Cai-Kim热力学构造，导致隐式修正的Friedmann方程；而模型II（本文提出并推导）通过熵积分处方获得，包含有效真空贡献。我们将两个模型用无量纲哈勃参数表述，包含辐射，施加精确的今日闭合条件，并使用隐式Friedmann方程的解析导数演化物理分支。我们用DESI DR2重子声学振荡和压缩的CMB似然（有或没有DES-Y5 Ia型超新星）约束模型。对于联合数据，模型I被驱动到显著较低的哈勃常数，$H_0\simeq62.4,\mathrm{km,s^{-1},Mpc^{-1}}$，并保持非幻影状态，$w_{\rm DE,0}\simeq-0.814$；相对于平坦$\Lambda$CDM，它被强烈否定。模型II在标准宇宙学参数上保持接近$\Lambda$CDM，给出$w_{\rm DE,0}\simeq-1.003$，而其两个熵扇区参数保持强烈简并。其最佳拟合似然与$\Lambda$CDM相当，但额外参数不被信息准则支持。这些结果表明，同一非加性熵的两种热力学实现在均匀背景层面具有截然不同的现象学后果。总之，基于熵的宇宙学的观测合理性关键取决于广义视界熵如何被纳入Friedmann动力学。
英文摘要
We investigate two late-time cosmological models generated by Kruglov's nonadditive entropy at the apparent horizon. Model I, originally derived by Kruglov, follows the Cai--Kim thermodynamic construction and leads to an implicit modified Friedmann equation, whereas Model II, proposed and derived in this work, is obtained from an entropy-integral prescription and contains an effective vacuum contribution. We formulate both models in terms of the dimensionless Hubble parameter, include radiation, impose exact present-day closure, and evolve the physical branch using analytic derivatives of the implicit Friedmann equations. We constrain the models with DESI DR2 baryon acoustic oscillations and a compressed CMB likelihood, with and without DES-Y5 Type-Ia supernovae. Model I is driven to a markedly lower Hubble constant, $H_0\simeq62.4,\mathrm{km,s^{-1},Mpc^{-1}}$ for the combined data, and remains non-phantom with $w_{\rm DE,0}\simeq-0.814$; it is strongly disfavoured relative to flat $Λ$CDM. Model II stays close to $Λ$CDM in the standard cosmological parameters and gives $w_{\rm DE,0}\simeq-1.003$, while its two entropy-sector parameters remain strongly degenerate. Its best-fit likelihood is comparable to $Λ$CDM, but the additional parameters are not supported by information criteria. These results show that the two thermodynamic realizations of the same nonadditive entropy have sharply different phenomenological consequences at the homogeneous-background level. In summary, the observational plausibility of entropy-based cosmology hinges critically on how the generalized horizon entropy is incorporated into the Friedmann dynamics.
Comments13 pages, 6 figures
