Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Composite Fermions with Spin at $\nu =1/2$   The model of Composite Fermions for describing interacting electrons in two
dimensions in the presence of a magnetic field is described. In this model,
charged Fermions are combined with an even number of magnetic flux quanta in
such a way that the external magnetic field is compensated on the average for
half filling of Landau levels and the interaction is incorporated into an
effective mass of the new composite particles. The fluctuations of the
Chern-Simons gauge field, which describes formally the flux attachment, induce
new interactions between the Composite Fermions. The effective interaction is
investigated with particular emphasis on the role of the electron spin at
filling factor $\nu=1/2$. For a system with equal numbers of spin-up and
spin-down electrons it is found that the dominant effective interaction is
attractive in the spin-singlet channel. This can induce a ground state
consisting of Cooper pairs of Composite Fermions that is separated from the
excited states by a gap. The results are used to understand recent spin
polarization measurements done in the region of the Fractional Quantum Hall
Effect at different constant filling factors.

14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
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The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
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The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph
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The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
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The categories of this paper are: solv-int
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The categories of this paper are: cs
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The categories of this paper are: q-fin
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The categories of this paper are: plasm-ph
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The categories of this paper are: chao-dyn