Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Kinetic transport in the two-dimensional periodic Lorentz gas   The periodic Lorentz gas describes an ensemble of non-interacting point
particles in a periodic array of spherical scatterers. We have recently shown
that, in the limit of small scatterer density (Boltzmann-Grad limit), the
macroscopic dynamics converges to a stochastic process, whose kinetic transport
equation is not the linear Boltzmann equation--in contrast to the Lorentz gas
with a disordered scatterer configuration. The present paper focuses on the
two-dimensional set-up, and reports an explicit, elementary formula for the
collision kernel of the transport equation.

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The categories of this paper are: cond-mat
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The categories of this paper are: cs
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The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
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The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: stat
25
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: hep-ex
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The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th