Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Concept of Classical and Quantum Free Acoustic Field   The concept of classical and quantum free acoustic (FA) field is
theoretically considered. The equations of the free acoustic field are derived.
They coincide in the mathematical form with Maxwell equations for the free
electromagnetic (EM) field. It is accentuated, that the equations in the
mathematical form of Maxwell equations for the free EM-field are universal
equations of the Nature. They describe any free complex-vector physical field,
vector-functions of which are analytical functions. In the case of a free
acoustic field, it seems to be the strong indication taking into account the
quantum Fermi liquid model of EM-field leading to the existence of phonons,
accompanying the process of a photon formation, that FA-field and free EM-field
are the display of the single united field, both the components of which can
propagate simultaneously [however, with different velocities], for instance, in
weakly absorbing media. The theory proposed can be the theoretical basis for
the practical realization of superconducting states at high temperature in the
materials with the strong interaction of electrons with acoustic field phonons
and with microwave photons in magnetic resonance conditions.

10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th