Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Probing strange stars and color superconductivity by r-mode
  instabilities in millisecond pulsars   R-mode instabilities in rapidly rotating quark matter stars (strange stars)
lead to specific signatures in the evolution of pulsars with periods below 2.5
msec, and may explain the apparent lack of very rapid pulsars. Existing data
seem consistent with pulsars being strange stars with a normal quark matter
phase surrounded by an insulating nuclear crust. In contrast, quark stars in a
color-flavor-locked (CFL) phase are ruled out. Two-flavor color
superconductivity (2SC) is marginally inconsistent with pulsar data.

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The categories of this paper are: physics
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: econ
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: dg-ga
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The categories of this paper are: q-bio
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The categories of this paper are: alg-geom
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The categories of this paper are: stat