Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reinterpretation of the Starobinsky model   The Starobinsky model of inflation, consistent with Planck 2015, has a
peculiar form of the action, which contains the leading Einstein term $R$, the
$R^2$ term with a huge coefficient, and negligible higher-order terms. We
propose an explanation of this form based on compactification of extra
dimensions. Once tuning of order $10^{-4}$ is accepted to suppress the linear
term $R$, we no longer have to suppress higher-oder terms, which give
nontrivial corrections to the Starobinsky model. We show our predictions of the
spectral index, its runnings, and the tensor-to-scalar ratio. Finally, we
discuss a possibility that quantum gravity may appear at the scale $\Lambda
\gtrsim 5 \times 10^{15}$ GeV.

33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci