Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Signature of a polyamorphic transition in the THz spectrum of vitreous
  GeO2   The THz spectrum of density fluctuations, $S(Q, \omega)$, of vitreous GeO$_2$
at ambient temperature was measured by inelastic x-ray scattering from ambient
pressure up to pressures well beyond that of the known $\alpha$-quartz to
rutile polyamorphic (PA) transition. We observe significant differences in the
spectral shape measured below and above the PA transition, in particular, in
the 30-80 meV range. Guided by first-principle lattice dynamics calculations,
we interpret the changes in the phonon dispersion as the evolution from a
quartz-like to a rutile-like coordination. Notably, such a crossover is
accompanied by a cusp-like behavior in the pressure dependence of the elastic
response of the system. Overall, the presented results highlight the complex
fingerprint of PA phenomena on the high-frequency phonon dispersion.

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The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
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The categories of this paper are: eess
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom