Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electron-phonon interaction and optical spectra of metals   Observed optical reflectivity in the infrared spectral region is compared
with theoretical predictions in a strongly coupled electron-phonon system.
Starting from a Froehlich Hamiltonian, the spectral functions and their
temperature dependence are derived. A full analysis including vertex
corrections leads to an expression for the optical conductivity \sigma(\omega)
which can be formulated in terms of the well known optical conductivity for a
quasi-isotropic system without vertex corrections. A numerical comparison
between the full result and the so-called ``extended'' Drude formula, its weak
coupling expansion, show little difference over a wide range of coupling
constants. Normal state optical spectra for the high-T_c superconductors
YBa_2Cu_3O_7 and La_{2-x}Sr_{x}CuO_4 at optimal doping are compared with the
results of model calculations. Taking the plasma frequency and \epsilon_\infty
from band structure calculations, the model has only one free parameter, the
electron-phonon coupling constant \lambda. In both materials the overall
behaviour of the reflectivity can be well accounted for over a wide frequency
range. Systematic differences exist only in the mid-infrared region. They
become more pronounced with increasing frequency, which indicates that a
detailed model for the optical response should include temperature dependent
mid-infrared bands.

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The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys