Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cosmic acceleration in asymptotically Ricci flat Universe   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 $R$.

9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
19
The categories of this paper are: eess
2
The categories of this paper are: math