Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Koppe's Work of 1948: A fundamental for non-equilibrium rate of particle
  production   In 1948, Koppe formulated an almost complete recipe for statistical-thermal
models including particle production, formation and decay of resonances,
temporal and thermal evolution of the interacting system, statistical
approaches and equilibrium condition in final state of the nuclear interaction.
As the rate of particle production was one of the basic assumptions, recalling
Koppe's work would be an essential input to be involved in the statistical
prediction of non-equilibrium particle production in recent and future
ultra-relativistic collisions.

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The categories of this paper are: physics
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The categories of this paper are: alg-geom
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The categories of this paper are: gr-qc
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The categories of this paper are: acc-phys
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The categories of this paper are: q-bio
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The categories of this paper are: math
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The categories of this paper are: q-alg
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The categories of this paper are: atom-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: cond-mat
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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: supr-con
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The categories of this paper are: ao-sci
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The categories of this paper are: mtrl-th
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The categories of this paper are: quant-ph