Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical Conductivity in the Copper Oxide Materials   The frequency- and temperature-dependent optical conductivity of the copper
oxide materials in the underdoped and optimal doped regimes are studied within
the t-J model. The conductivity spectrum shows the unusual behavior at low
energies and anomalous midinfrared peak in the low temperatures. However, this
midinfrared peak is severely depressed with increasing temperatures, and
vanishes at higher temperatures.

16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga