Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Van der Waals and Casimir interactions between atoms and carbon
  nanotubes   The van der Waals and Casimir interactions of a hydrogen atom (molecule) with
a single-walled and a multiwalled carbon nanotubes are compared. It is shown
that the macroscopic concept of graphite dielectric permittivity is already
applicable for nanotubes with only two or three walls. The absorption of
hydrogen atoms by a nanotube at separations below one nanometer is considered.
The lateral force due to exchange repulsion moves the atom to a position above
the cell center, where it is absorbed by the nanotube because the repulsive
force cannot balance the van der Waals attraction.

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The categories of this paper are: physics
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The categories of this paper are: solv-int
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The categories of this paper are: stat
31
The categories of this paper are: ao-sci
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The categories of this paper are: nlin
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The categories of this paper are: hep-th
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The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
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The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
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The categories of this paper are: adap-org