Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurements of the Composite Fermion masses from the spin polarization
  of 2-D electrons in the region $1<\nu<2$   Measurements of the reflectivity of a 2-D electron gas are used to deduce the
polarization of the Composite Fermion hole system formed for Landau level
occupancies in the regime 1<\nu<2. The measurements are consistent with the
formation of a mixed spin CF system and allow the density of states or
`polarization' effective mass of the CF holes to be determined. The mass values
at \nu=3/2 are found to be ~1.9m_{e} for electron densities of 4.4 x 10^{11}
cm^{-2}, which is significantly larger than those found from measurements of
the energy gaps at finite values of effective magnetic field.

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The categories of this paper are: astro-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: gr-qc
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The categories of this paper are: stat
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The categories of this paper are: adap-org
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The categories of this paper are: cs
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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-lat
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex
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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-ph
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The categories of this paper are: physics