Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Strong-Coupling Expansions for Multiparticle Excitations: Continuum and
  Bound States   We present a new linked cluster expansion for calculating properties of
multiparticle excitation spectra to high orders. We use it to obtain the
two-particle spectra for systems of coupled spin-half dimers. We find that even
for weakly coupled dimers the spectrum is very rich, consisting of many bound
states. The number of bound states depends on both geometry of coupling and
frustration. Many of the bound states can only be seen by going to sufficiently
high orders in the perturbation theory, showing the extended character of the
pair-attraction.

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The categories of this paper are: q-bio
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The categories of this paper are: econ
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The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: ao-sci
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The categories of this paper are: stat
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-alg