涌现分形分维宇宙学的观测约束
Observational Constraints on Emergent Fractional Fractal Cosmology
AI总结：
本研究通过多组宇宙学观测数据的联合似然分析，对涌现分形分维（EFF）宇宙学模型进行约束，得出当前观测对标准模型的分形扩展及相关偏离有严格限制的结论。
AI中文摘要：
我们通过背景和扰动层面最新宇宙学观测的联合似然分析，对涌现分形分维（Emergent Fractional Fractal，EFF）宇宙学模型进行约束。在该框架中，引入有效分形维数$d$来参数化与标准宇宙学模型可能存在的分维偏离。我们考虑了三组数据集组合：（i）包括PantheonPlus Ia型超新星、$H(z)$测量以及增长率测量$fσ_8$的晚期（LT）观测；（ii）晚期观测结合DESI DR2 BAO和大爆炸核合成（BBN）；（iii）晚期观测结合DESI DR2 BAO和CMB距离先验。纳入CMB距离先验后，分形维数在$1σ$置信水平下被约束为$d = 2.0004^{+0.0006}_{-0.0003}$。使用赤池信息准则（AIC）进行的模型比较显示，EFF模型与$Λ$CDM模型对观测数据的拟合效果相当，而贝叶斯信息准则（BIC）则更偏好更简单的$Λ$CDM模型，因其参数空间更小。这些结果表明，当前宇宙学观测对标准宇宙学框架的分形扩展以及与$Λ$CDM模型的可能偏离施加了严格约束。
英文摘要：
We constrain the Emergent Fractional Fractal (EFF) cosmological model through a joint likelihood analysis of recent cosmological observations at the background and perturbation levels. In this framework, an effective fractal dimension $d$ is introduced to parameterize possible fractional deviations from the standard cosmological model. We consider three combinations of datasets: (i) late-time (LT) observations including PantheonPlus Type Ia supernovae, $H(z)$ measurements, and growth-rate measurements $fσ_8$; (ii) LT combined with DESI DR2 BAO and Big Bang nucleosynthesis (BBN); and (iii) LT combined with DESI DR2 BAO and CMB distance priors. With the inclusion of CMB distance priors, the fractal dimension is constrained to $d = 2.0004^{+0.0006}_{-0.0003}$ at the $1σ$ confidence level. Model comparison using the Akaike Information Criterion (AIC) shows that the EFF and $Λ$CDM models fit the observational data equally well, while the Bayesian Information Criterion (BIC) favors the simpler $Λ$CDM model because of its smaller parameter space. These results show that current cosmological observations place strong constraints on fractal extensions of the standard cosmological framework and possible deviations from the $Λ$CDM model.
