Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cosmological bounces in spatially flat FRW spacetimes in metric f(R)
  gravity   The present work analyzes the various conditions in which there can be a
bouncing universe solution in f(R) gravity. In the article an interesting
method, to analyze the bouncing FRW solutions in a spatially flat universe
using f(R) gravity models using an effective Einstein frame description of the
process, is presented. The analysis shows that a cosmological bounce in the
f(R) theory need not be described by an equivalent bounce in the Einstein frame
description of the process where actually there may be no bounce at all.
Nevertheless the Einstein frame description of the bouncing phenomena turns out
to be immensely important as the dynamics of the bounce becomes amenable to
logic based on general relativistic intuition. The theory of scalar
cosmological perturbations in the bouncing universe models in $f(R)$ theories
has also been worked out in the Einstein frame.

21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph