Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Brillouin and Boson peaks in Glasses from vector Euclidean Random Matrix
  Theory   A simple model of harmonic vibrations in topologically disordered systems,
such as glasses and supercooled liquids, is studied analytically by extending
Euclidean Random Matrix Theory to include vector vibrations. Rather generally,
it is found that i) the dynamic structure factor shows sound-like Brillouin
peaks whose longitudinal/transverse character can only be distinguished for
small transferred momentum, p, ii) the model presents a mechanical instability
transition at small densities, for which scaling laws are analytically
predicted and confirmed numerically, iii) the Brillouin peaks persist deep into
the unstable phase, the phase transition being noticeable mostly in their
linewidth, iv) the Brillouin linewidth scales like p square in the stable
phase, and like p in the unstable one. The analytical results are checked
numerically for a simple potential. The main features of glassy vibrations
previously deduced from scalar ERMT are not substantially altered by these new
results.

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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: comp-gas
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: econ
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The categories of this paper are: chem-ph
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The categories of this paper are: nlin
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The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math