Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonequilibrium Temperature for Open Boson and Fermion Systems   The effective theory of an open boson or fermion system is studied, which
evolves out of equilibrium with time-dependent Hamiltonian $\hat{H}(t)$. A
measure of nonequilibrium temperature for the open system evolving from an
equilibrium is proposed as the time-averaged energy expectation value $T(t) =
T_i(\bar{< \hat{H} (t) >_{\Psi}}/ \bar{< \hat{I} (t) >_{\Psi}})$, where
$\hat{I} (t)$, the action operator, satisfies the quantum Liouville-von Neumann
equation and determines the true density operator. It recovers the result for
the adiabatic (quasi-equilibrium) and nonadiabatic (out of equilibrium)
evolution from one static Hamiltonian to another and takes into account the
particle production due to the intermediate processes.

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The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
26
The categories of this paper are: bayes-an
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The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
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The categories of this paper are: stat
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom