Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inflationary cosmology in modified gravity theories   We review inflationary cosmology in modified gravity such as $R^2$ gravity
with its extensions in order to generalize the Starobinsky inflation model. In
particular, we explore inflation realized by three kinds of effects:
modification of gravity, the quantum anomaly, and the $R^2$ term in loop
quantum cosmology. It is explicitly demonstrated that in these inflationary
models, the spectral index of scalar modes of the density perturbations and the
tensor-to-scalar ratio can be consistent with the Planck results. Bounce
cosmology in $F(R)$ gravity is also explained.

21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat