Current cosmological observations allow for deviations from the standard growth of large-scale structures in the universe. These deviations could indicate modifications to General Relativity on cosmological scales or suggest the dynamical nature of dark energy. It is important to characterize these departures in a model-independent manner to understand their significance objectively and explore their fundamental causes more generically across a wider spectrum of theories and models. In this paper, we compress the information from redshift-space distortion data into 2–3 parameters μi, which control the ratio between the effective gravitational coupling in Poisson's equation and Newton's constant in several redshift bins in the late universe. We test the efficiency of this compression using mock final-year data from the Dark Energy Spectroscopic Instrument (DESI) and considering three different models within the class of effective field theories of dark energy. The constraints on the parameters of these models, obtained from both the direct fit to the data and the projection of the compressed parameters onto the parameters of the models, are fully consistent, demonstrating the method's good performance. Then, we apply it to current data and find hints of a suppressed matter growth in the universe at ∼ 2.7σ C.L., in full accordance with previous works in the literature. Finally, we perform a forecast with DESI data and show that the uncertainties on the parameters μ1 at z < 1 and μ2 at 1 < z < 3 are expected to decrease by approximately 40% and 20%, respectively, compared to those obtained with current data. Additionally, we project these forecasted constraints onto the parameters of the aforesaid models.

中文翻译：

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为后期修正的重力模型高效压缩红移空间畸变数据


目前的宇宙学观测允许与宇宙中大尺度结构的标准增长存在偏差。这些偏差可能表明广义相对论在宇宙学尺度上的改变，或者表明暗能量的动力学性质。重要的是要以独立于模型的方式描述这些偏离，以客观地理解它们的重要性，并在更广泛的理论和模型中更普遍地探索它们的根本原因。在本文中，我们将来自红移空间扭曲数据的信息压缩为 2-3 个参数 μi，这些参数控制泊松方程中的有效引力耦合与宇宙晚期几个红移区间中的牛顿常数之间的比率。我们使用来自暗能量光谱仪 （DESI） 的模拟年终数据来测试这种压缩的效率，并考虑了暗能量有效场论类别中的三种不同模型。这些模型对参数的直接拟合和压缩参数对模型参数的投影是完全一致的，证明了该方法的良好性能。然后，我们将其应用于当前数据，并发现宇宙中 ∼ 2.7σ C.L. 存在被抑制物质增长的迹象，这与以前的文献工作完全一致。最后，我们使用 DESI 数据进行预测，结果表明，与当前数据相比，z < 1 和 1 < z < 3 处的 μ2 参数 μ1 的不确定性预计将分别降低约 40% 和 20%。此外，我们将这些预测的约束条件投影到上述模型的参数上。