Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Scale Factor Dependent Equations of State for Curvature Inspired Dark
  Energy, Phantom Barrier and Late Cosmic Acceleration   Here, it is found that dark energy and dark matter emerge from the
gravitational sector, if non-linear term of scalar curvature is added to
Einstein-Hilbert lagrangian. An equation of state for dark energy, having the
form $p_{\rm de} = - \rho_{\rm de} + f(a) (with $p_{\rm de}(\rho_{\rm de})$
being the pressure(density) for dark energy, $f(a)$ being a function of scale
feactor $a(t)$ and $t$ being the cosmic time) is explored. Interestingly, this
equation of state leads to a phantom barrier ${\rm w}_{\rm de} = p_{\rm
de}/\rho_{\rm de} = - 1$ at $a = a_{\rm w}$. It is found that when $a < a_{\rm
w}, {\rm w}_{\rm de} > - 1$ and ${\rm w}_{\rm de} < - 1$ for $a > a_{\rm w},$
showing a transition from non-phantom to phantom phase at $a = a_{\rm w} < a_0
(a_0$ being current scale factor of the universe). PACS no.: 98.80 Cq.

9
The categories of this paper are: nlin
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
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
31
The categories of this paper are: ao-sci