Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Modeling of the electronic state of the High-Temperature Superconductor
  LaCuO: Phonon dynamics and charge response   A modeling of the normal state of the p-doped high-temperature
superconductors (HTSC's) is presented. This is achieved starting from a more
conventional metallic phase for optimal- and overdoping and passing via the
underdoped to the insulating state by consecutive orbital selective
compressibility-incompressibility transitions in terms of sum rules for the
charge response. The modeling is substantiated by corresponding phonon
calculations. Extending investigations of the full dispersion and in particular
of the strongly doping dependent anomalous phonon modes in LaCuO, which so far
underpin our treatment of the density response of the electrons in the p-doped
HTSC's, gives additional support for the modeling of the electronic state,
compares well with recent experimental data and predicts the dispersion for the
overdoped regime. Moreover, phonon densities of states have been calculated and
compared for the insulating, underdoped, optimally doped and overdoped state of
LaCuO. From our modeling of the normal state a consistent picture of the
superconducting phase also can be extracted qualitatively pointing in the
underdoped regime to a phase ordering transition. On the other hand, the
modeling of the optimal and overdoped state is consistent with a quasi-particle
picture with a well defined Fermi surface. Thus, in the latter case a Fermi
surface instability with an evolution of pairs of well defined quasiparticles
is possible and can lead to a BCS-type ordering. So, it is tempting to
speculate that optimal $T_C$ in the HTSC's marks a crossover region between
these two forms of ordering.

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The categories of this paper are: nlin
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The categories of this paper are: nucl-th
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The categories of this paper are: funct-an
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The categories of this paper are: math
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The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
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The categories of this paper are: astro-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom