Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electron spin resonance in a dilute magnon gas as a probe of magnon
  scattering resonances   We study the electron spin resonance in a dilute magnon gas that is realized
in a ferromagnetic spin system at low temperature. A quantum cluster expansion
is developed to show that the frequency shift of the single-magnon peak changes
its sign and the linewidth reaches its maximum across a scattering resonance
between magnons. Such characteristic behaviors are universal and can be used to
experimentally locate the two-magnon resonance when an external parameter such
as pressure is varied. Future achievement of the two-magnon resonance may have
an impact comparable to the Feshbach resonance in ultracold atoms and will open
up a rich variety of strongly correlated physics such as the recently proposed
Efimov effect in quantum magnets. We also suggest how the emergence of an
Efimov state of three magnons and its binding energy may be observed with the
electron spin resonance.

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The categories of this paper are: mtrl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: plasm-ph
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The categories of this paper are: stat
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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: nucl-th
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The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
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The categories of this paper are: supr-con
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The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: patt-sol
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The categories of this paper are: atom-ph
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The categories of this paper are: solv-int