Kunz Martin, Sapone Domenico
Département de Physique Théorique, Université de Genève, 24 quai Ernest Ansermet, CH-1211 Genève 4, Switzerland.
Phys Rev Lett. 2007 Mar 23;98(12):121301. doi: 10.1103/PhysRevLett.98.121301. Epub 2007 Mar 21.
There is now strong observational evidence that the expansion of the Universe is accelerating. The standard explanation invokes an unknown "dark energy" component. But such scenarios are faced with serious theoretical problems, which has led to increased interest in models where instead general relativity is modified in a way that leads to the observed accelerated expansion. The question then arises whether the two scenarios can be distinguished. Here we show that this may not be so easy, demonstrating explicitly that a generalized dark energy model can match the growth rate of the Dvali-Gabadadze-Porrati model and reproduce the 3+1 dimensional metric perturbations. Cosmological observations are then unable to distinguish the two cases.
现在有强有力的观测证据表明宇宙正在加速膨胀。标准的解释引入了一种未知的“暗能量”成分。但这类设想面临着严重的理论问题，这使得人们对一些模型的兴趣增加，在这些模型中，广义相对论以一种能导致观测到的加速膨胀的方式被修改。于是问题就出现了，这两种设想是否能够被区分开来。在此我们表明这可能并非易事，通过明确证明一个广义暗能量模型能够匹配德瓦利-加巴达泽-波拉蒂模型的增长率并重现3 + 1维的度规微扰。宇宙学观测因而无法区分这两种情况。
