http://arxiv.org/abs/1711.08026
We analyze the evolution of a Friedmann-Robertson-Walker spacetime within the framework of $f(R)$ metric gravity using an exponential model. We show that $f(R)$ gravity may lead to a vanishing effective cosmological constant in the far future (i.e. $R\rightarrow 0$) and yet produce a transient accelerated expansion at present time with a potentially viable cosmological history. This is in contrast with several $f(R)$ models which, while viable, produce in general a non-vanishing effective cosmological constant asymptotically in time ($R\rightarrow 4\Lambda_{\rm eff}$). We also show that relativistic {stars in asymptotically flat spacetimes can be supported within this framework without encountering any singularity, notably in the Ricci scalar $R$.
L. Jaime and M. Salgado
Thu, 23 Nov 17
30/52
Comments: 12 pages, 18 figures in 9 panels