Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ballistic Composite Fermions in Semiconductor Nanostructures   We report the results of two fundamental transport measurements at a Landau
level filling factor $\nu$ of 1/2. The well known ballistic electron transport
phenomena of quenching of the Hall effect in a mesoscopic cross-junction and
negative magnetoresistance of a constriction are observed close to B~=~0 and
$\nu~=~ 1/2$. The experimental results demonstrate semi-classical charge
transport by composite fermions, which consist of electrons bound to an even
number of flux quanta.

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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: comp-gas
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
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The categories of this paper are: hep-th
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The categories of this paper are: dg-ga
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
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The categories of this paper are: chem-ph