Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Wigner-Weyl calculus in Keldysh technique   We discuss the non-equilibrium dynamics of condensed matter/quantum field
systems in the framework of Keldysh technique. In order to deal with the
inhomogeneous systems we use the Wigner-Weyl formalism. Unification of the
mentioned two approaches is demonstrated on the example of Hall conductivity.
We express Hall conductivity through the Wigner transformed two-point Green's
functions. We demonstrate how this expression is reduced to the topological
number in thermal equilibrium at zero temperature. At the same time both at
finite temperature and out of equilibrium the topological invariance is lost.
Moreover, Hall conductivity becomes sensitive to interaction corrections.

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The categories of this paper are: bayes-an
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The categories of this paper are: dg-ga
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The categories of this paper are: mtrl-th
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The categories of this paper are: math
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The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: comp-gas
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The categories of this paper are: quant-ph
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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: physics
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The categories of this paper are: nucl-th