Sultana Joseph, Melia Fulvio, Kazanas Demosthenes
Department of Mathematics, Faculty of Science, University of Malta, Msida MSD2080, Malta.
Department of Physics, The Applied Math Program, and Department of Astronomy, The University of Arizona, Tucson Arizona 85721, USA.
Phys Rev D. 2019 May 15;99(10). doi: 10.1103/PhysRevD.99.103505. Epub 2019 May 6.
We consider here some popular () models generally viewed as possible alternatives to the existence of dark energy in General Relativity. For each of these, we compute the redshift at which the angular diameter distance () is expected to reach its maximum value. This turning point in () was recently measured in a model-independent way using compact quasar cores and was found to occur at = 1.70 ± 0.20. We compare the predictions of for the () models with this observed value to test their viability at a deeper level than has been attempted thus far, thereby quantifying an important observational difference between such modified gravity scenarios and standard Lambda Cold Dark Matter (ΛCDM) cosmology. Our results show that, while the most popular () models today are consistent with this measurement to within 1, the turning point will allow us to prioritize these alternative gravity theories as the measurement precision continues to improve, particularly with regard to how well they mitigate the tension between the predictions of ΛCDM and the observations. For example, while the Hu-Sawicki version of () increases this tension, the Starobinky model reduces it.
我们在此考虑一些普遍被视为广义相对论中暗能量存在的可能替代方案的流行（）模型。对于其中每一个模型，我们计算红移，在该红移处角直径距离（）预计会达到其最大值。最近利用致密类星体核心以与模型无关的方式测量了（）中的这个转折点，发现其出现在 = 1.70 ± 0.20 处。我们将（）模型的预测值与这个观测值进行比较，以比迄今为止所尝试的更深入的层面检验它们的可行性，从而量化这种修正引力情景与标准冷暗物质（ΛCDM）宇宙学之间的一个重要观测差异。我们的结果表明，虽然如今最流行的（）模型与该测量结果在 1 的范围内一致，但随着测量精度不断提高，转折点将使我们能够对这些替代引力理论进行优先级排序，特别是关于它们在多大程度上缓解了 ΛCDM 预测与观测之间的矛盾。例如，虽然（）的胡 - 萨维奇版本加剧了这种矛盾，但斯塔罗宾斯基模型则减少了这种矛盾。
