Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Population trapping and inversion in ultracold Fermi gases by excitation
  of the optical lattice - Non-equilibrium Floquet-Keldysh description   A gas of ultracold interacting quantum degenerate Fermions is considered in a
three dimensional optical lattice which is externally modulated in the fre-
quency and the amplitude. This theoretical study utilizes the Keldysh formalism
to account for the system being out of thermodynamical equilibrium. A dynamical
mean field theory, extended to non-equilibrium, is presented to calculate
characteristic quantities such as the local density of states and the
non-equilibrium distribution function. A dynamics Franz-Keldysh splitting is
found which accounts for the non-equilibrium modification of the underlying
bandstructure. The found characteristic Floquet-fan like bandstructure accounts
for the quantized nature of the effect over all frequency space.

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The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
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The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org
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The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
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The categories of this paper are: math-ph
30
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: hep-th