Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electromagnetic response of superconductors and optical sum rule   The interrelation between the condensation energy and the optical sum rules
has been investigated. It has been shown that the so called 'partial' sum rule
violation is related mainly to a temperature dependence of the relaxation rate
rather than to the appearance of superconductivity itself. Moreover, we
demonstrate that the experimental data on the temperature dependence of the
optical sum rule can be explained rather well by an account of strong
electron-phonon interaction.

10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph