Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A fermion phenomenology of low-temperature strongly-noncrystalline
  solids   Insisting on the relevance of spin-statistics theorem, I propose that
anomalous low-energy excitations of strongly-noncrystalline solids (SNSs),
observed at low temperatures T < 1 K, are fermions, which are localized and
weakly interacting. This phenomenological theory rationalizes all low-energy
quantum many-body states of SNSs as Goldstone bosons-phonons and
half-integer-spin fermions. Fermi glass, rather than isolated two-level systems
(TLSs), appears to be a consistent theory of various thermal and nonlinear
response properties of SNSs. A robust consequence of this theory is nearly
constant-in-energy density of fermion states near Fermi energy, which in turn
implies linear-in-temperature specific heat and frequency-independent sound
internal friction. Consistent parameters of Landau-Fermi glass are calculated
on theoretical grounds as well as from experimental data.

23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ