Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: In-Plane Spectral Weight Shift of Charge Carriers in $YBa_2Cu_3O_{6.9}$   The temperature dependent redistribution of the spectral weight of the
$CuO_2$ plane derived conduction band of the $YBa_2Cu_3O_{6.9}$ high
temperature superconductor (T_c = 92.7 K) was studied with wide-band (from 0.01
to 5.6 eV) spectroscopic ellipsometry. A superconductivity - induced transfer
of the spectral weight involving a high energy scale in excess of 1 eV was
observed. Correspondingly, the charge carrier spectral weight was shown to
decrease in the superconducting state. The ellipsometric data also provide
detailed information about the evolution of the optical self-energy in the
normal and superconducting states.

26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph