Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Adiabatic And Entropy Perturations In Inflationary Models Based On
  Non-linear Sigma Model   The scalar perturbations in inflationary models, based on a two-component
diagonal non-linear sigma model, are considered. For inhomogeneities generated
at an inflationary stage, the law of motion of the comoving curvature ${\cal
R}$ is obtained (without using the slow roll approximations). A formal
expressions for the power spectrum and its spectral index are obtained, which
are valid and after the slow-roll stage. As an example, an inflationary model
with a massive scalar field and quadratic curvature corrections is studied
numerically.

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The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
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The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci