Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pure double-layer bubbles in quadratic F(R) gravity   We present a class of spherically symmetric spacetimes corresponding to
bubbles separating two regions with constant values of the scalar curvature, or
equivalently with two different cosmological constants, in quadratic F(R)
theory. The bubbles are obtained by means of the junction formalism, and the
matching hypersurface supports in general a thin shell and a gravitational
double layer. In particular, we find that pure double layers are possible for
appropriate values of the parameters of the model whenever the quadratic
coefficient is negative. This is the first example of a pure double layer in a
gravitational theory.

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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: q-alg
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The categories of this paper are: physics
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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: comp-gas