Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: No-Go Theorem for Gauss-Bonnet Inflation without Inflaton Potential   Recently, an interesting inflationary scenario, named Gauss-Bonnet inflation,
is proposed by Kanti et al.~\cite{Kanti:2015pda,Kanti:2015dra}. In the model,
there is no inflaton potential but the inflaton couples to the Guass-Bonnet
term. In the case of quadratic coupling, they find inflation occurs with
graceful exit. The scenario is attractive because of the natural set-up.
However, we show there exists the gradient instability in the tensor
perturbations in this inflationary model. We further prove the no-go theorem
for the Gauss-Bonnet inflation without an inflaton potential.

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The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
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The categories of this paper are: adap-org
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The categories of this paper are: q-bio
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The categories of this paper are: cond-mat
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The categories of this paper are: quant-ph
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The categories of this paper are: eess
1
The categories of this paper are: cs
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: nlin
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg