Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Decoherence processes of a quantum two-level system coupled to a
  fermionic environment   We study decoherence processes of an S = 1/2 localized spin coupled to
conduction band electrons in a metal or a semiconductor via an Ising-like
interaction. We derive master equations for the density matrix of the localized
spin, by tracing out all degrees of freedom in the conduction electron system
based on the linked-cluster-expansion technique. It is found that the
decoherence occurs more rapidly for the metallic case than for semiconducting
case.

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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: bayes-an
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The categories of this paper are: math-ph
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
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The categories of this paper are: funct-an
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The categories of this paper are: supr-con
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The categories of this paper are: q-fin
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The categories of this paper are: q-alg
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The categories of this paper are: stat
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The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
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The categories of this paper are: econ