Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Temperature Dependence of Optical Spectra for the CDW Gap and Optical
  Phonons in BaBiO_3   We have studied the temperature dependence of the optical spectra for the CDW
gap and optical phonons in a single crystal of BaBiO_3 and a film deposited by
laser ablation. The integrated optical conductivity for optical phonons
decreases rapidly with increasing temperature above 150 K, while the
single-particle excitation across the CDW gap remains constant.

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The categories of this paper are: hep-th
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The categories of this paper are: supr-con
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The categories of this paper are: econ
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The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
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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: math
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The categories of this paper are: stat
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The categories of this paper are: nucl-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-bio
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The categories of this paper are: patt-sol
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The categories of this paper are: gr-qc