Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical conductivity of doped manganites: Comparison of ferromagnetic
  Kondo Lattice Models with and without orbital degeneracy   The optical conductivity of the double exchange and the orbital degenerate
Kondo lattice Hamiltonian (orbital t-J model) are invetigated by means of
finite temperature diagonalization for different doping concentrations. The
temperature dependence of sum rules, kinetic energy and Drude weight are
studied. In particular it is shown that the double exchange model cannot
explain the anomalous absorption in the uniform ferromagnetic phase of
manganites discovered Okimoto et al. [Phys. Rev. Lett. 75, 109 (1995)]. The
orbital t-J model explains the increase of the anomalous absorption with
decreasing temperature, its energy scale (~1 eV) and intensity. It also
explains the appearance of the additional narrow Drude peak at low temperature.

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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
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The categories of this paper are: hep-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
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The categories of this paper are: nlin
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The categories of this paper are: hep-lat