Lazkoz Ruth, Ortiz-Baños María, Salzano Vincenzo
1Department of Theoretical Physics, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao, Spain.
2Faculty of Mathematics and Physics, Institute of Physics, University of Szczecin, Wielkopolska 15, 70-451 Szczecin, Poland.
Eur Phys J C Part Fields. 2018;78(3):213. doi: 10.1140/epjc/s10052-018-5711-6. Epub 2018 Mar 13.
It is a very well established matter nowadays that many modified gravity models can offer a sound alternative to General Relativity for the description of the accelerated expansion of the universe. But it is also equally well known that no clear and sharp discrimination between any alternative theory and the classical one has been found so far. In this work, we attempt at formulating a different approach starting from the general class of () theories as test probes: we try to reformulate () Lagrangian terms as explicit functions of the redshift, i.e., as (). In this context, the () setting to the consensus cosmological model, the [Formula: see text]CDM model, can be written as a polynomial including just a constant and a third-order term. Starting from this result, we propose various different polynomial parameterizations (), including new terms which would allow for deviations from [Formula: see text]CDM, and we thoroughly compare them with observational data. While on the one hand we have found no statistically preference for our proposals (even if some of them are as good as [Formula: see text]CDM by using Bayesian Evidence comparison), we think that our novel approach could provide a different perspective for the development of new and observationally reliable alternative models of gravity.
如今，一个已经确立得很好的事实是，许多修正引力模型可以为广义相对论提供一个合理的替代方案，用于描述宇宙的加速膨胀。但同样众所周知的是，到目前为止，在任何替代理论和经典理论之间都没有发现清晰明确的区分。在这项工作中，我们尝试从（）理论的一般类别作为测试探针出发，制定一种不同的方法：我们试图将（）拉格朗日项重新表述为红移的显式函数，即（）。在这种情况下，（）设定到共识宇宙学模型，即ΛCDM模型，可以写成一个仅包含一个常数和一个三阶项的多项式。从这个结果出发，我们提出了各种不同的多项式参数化（），包括允许偏离ΛCDM的新项，并将它们与观测数据进行了全面比较。一方面，我们发现对于我们的提议没有统计学上的偏好（即使通过贝叶斯证据比较，其中一些与ΛCDM一样好），但我们认为我们的新方法可以为开发新的、观测上可靠的替代引力模型提供一个不同的视角。
