Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Steric repulsion and van der Waals attraction between flux lines in
  disordered high Tc superconductors   We show that in anisotropic or layered superconductors impurities induce a
van der Waals attraction between flux lines. This attraction together with the
disorder induced repulsion may change the low B - low T phase diagram
significantly from that of the pure thermal case considered recently by Blatter
and Geshkenbein [Phys. Rev. Lett. 77, 4958 (1996)].

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The categories of this paper are: funct-an
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The categories of this paper are: astro-ph
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
3
The categories of this paper are: physics
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The categories of this paper are: ao-sci
2
The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-th
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg