Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analytic expansions of multi-hadron finite-volume energies: I.
  Two-particle states   We derive analytic expansions for the finite-volume energies of
weakly-interacting two-particle systems, using the general relations between
scattering amplitudes and energies derived by L\"uscher and others. The
relations hold for ground and excited states with both zero and non-zero total
momentum in the finite-volume frame. A number of instructive aspects arise in
the derivation, including the role of accidental degeneracies and the
importance of defining a power-counting scheme in the expansions. The results
give intuition concerning the imprint of weakly-interacting systems on the
energy spectrum, while also providing a useful basis for the analogous results
concerning three-particle excited states, to appear.

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The categories of this paper are: patt-sol
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ex
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The categories of this paper are: cs
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The categories of this paper are: math-ph
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-th
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The categories of this paper are: nlin
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The categories of this paper are: physics
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: solv-int
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: chem-ph