http://arxiv.org/abs/1904.07608
A large number of dark energy and modified gravity models lead to the same expansion history of the Universe, hence, making it difficult to distinguish them from observations. To make the calculations transparent, we consider $f(R)$ gravity with a pressureless matter without making any assumption about the form of $f(R)$. Using the late-time expansion history realizations constructed by Shafieloo et al., we explicitly show that one of the Bardeen potential $\Psi$ is suppressed compared to $\Phi$ for any $f(R)$ model that lead to late-time acceleration. For an arbitrary $f(R)$ model, we explicitly show that $|\Psi + \Phi|$ and its time-derivative are about an order larger than the $\Lambda$CDM model at lower redshifts. We discuss the implications of the results for the cosmological observations.
J. Johnson and S. Shankaranarayanan
Wed, 17 Apr 19
65/75
Comments: 21 figures, 22 pages
You must be logged in to post a comment.