从增长数据看修正引力：拟合优度与引力耦合
Modified Gravity from growth data: goodness-of-fit and gravitational coupling
浏览论文内容
中文总结 AI 辅助
本文利用增长数据约束三个F(R)修正引力模型，通过MCMC和拟合优度统计发现模型间难以区分，但重构引力耦合μ(z)后，R^2-AB模型因与Planck 2018存在3.2σ张力而被排除。
中文摘要 AI 辅助
虽然仅凭背景膨胀数据无法区分不同的宇宙学模型，但大尺度结构的增长直接探测了潜在的引力理论，为区分广义相对论及其修正提供了途径。在本工作中，我们利用增长率$f(z)$和物质涨落幅度$\sigma_8(z)$的测量数据，约束了三个具有代表性的$F(R)$修正引力模型（Starobinsky、Hu-Sawicki和$R^2$修正的Appleby-Battye）。我们的分析结合了MCMC参数估计、高斯过程重构以及拟合优度统计量，包括Akaike信息准则（AIC）和Bayesian信息准则（BIC）。所有被研究的模型对当前增长数据提供了统计上可比较的拟合，信息准则差异过小，无法确立对任何特定情景的偏好。为了克服这种简并性，我们从MCMC后验样本中重构了有效引力耦合$\mu(z)$，提供了一个物理动机明确的诊断量，补充了标准的拟合优度准则。Starobinsky和Hu-Sawicki模型预测了与广义相对论的适度偏离，与$\mu(z)$和$S_8$的约束保持兼容。相比之下，$R^2$-AB模型预测$\mu_0 \sim 3.5$和$S_8 = 0.638$，与Planck 2018存在$3.2\sigma$的张力，尽管其统计表现具有竞争力，但在物理上不受青睐。
英文摘要
While background expansion data alone cannot discriminate among cosmological models, the growth of large-scale structures directly probes the underlying theory of gravity, offering a path to distinguish General Relativity from its modifications. In this work, we constrain three representative $F(R)$ modified gravity models (Starobinsky, Hu-Sawicki, and $R^2$-corrected Appleby-Battye) using measurements of the growth rate $f(z)$ and the matter fluctuation amplitude $σ_8(z)$. Our analyses combine MCMC parameter estimation, Gaussian Process reconstructions, and goodness-of-fit statistics including Akaike information criterion (AIC) and Bayesian information criterion (BIC). All investigated models provide statistically comparable fits to the current growth data, with information criteria differences too small to establish a preference for any particular scenario. To overcome this degeneracy, we reconstruct the effective gravitational coupling $μ(z)$ from the MCMC posterior samples, providing a physically motivated diagnostic that complements standard goodness-of-fit criteria. The Starobinsky and Hu-Sawicki models predict moderate departures from General Relativity, remaining compatible with constraints on both $μ(z)$ and $S_8$. In contrast, the $R^2$-AB model predicts $μ_0 \sim 3.5$ and $S_8 = 0.638$, a $3.2σ$ tension with Planck 2018, rendering it physically disfavored despite its competitive statistical performance.
发表机构
- Observatório Nacional（国家天文台）
- Universidade Federal do Espírito Santo（圣埃斯皮里图联邦大学）
机构由 AI 辅助整理，请以论文原文为准。
