Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Coherent-Potential approximation for diffusion and wave propagation in
  topologically disordered systems   Using Gaussian integral transform techniques borrowed from
functional-integral field theory and the replica trick we derive a version of
the coherent-potential approximation (CPA) suited for describing ($i$) the
diffusive (hopping) motion of classical particles in a random environment and
($ii$) the vibrational properties of materials with spatially fluctuating
elastic coefficients in topologically disordered materials. The effective
medium in the present version of the CPA is not a lattice but a homogeneous and
isotropic medium, representing an amorphous material on a mesoscopic scale. The
transition from a frequency-independent to a frequency-dependent diffusivity
(conductivity) is shown to correspond to the boson peak in the vibrational
model. The anomalous regimes above the crossover are governed by a complex,
frequency-dependent self energy. The boson peak is shown to be stronger for
non-Gaussian disorder than for Gaussian disorder. We demonstrate that the
low-frequency non-analyticity of the off-lattice version of the CPA leads to
the correct long-time tails of the velocity autocorrelation function in the
hopping problem and to low-frequency Rayleigh scattering in the wave problem.
Furthermore we show that the present version of the CPA is capable to treat the
percolative aspects of hopping transport adequately.

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The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
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The categories of this paper are: ao-sci
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The categories of this paper are: eess
22
The categories of this paper are: chao-dyn