Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum hydrodynamics of spinning particles in electromagnetic and
  torsion fields   We develop a many-particle quantum-hydrodynamical model of fermion matter
interacting with the external classical electromagnetic and
gravitational/inertial and torsion fields. The consistent hydrodynamical
formulation is constructed for the many-particle quantum system of Dirac
fermions on the basis of the nonrelativistic Pauli-like equation obtained via
the Foldy-Wouthuysen transformation. With the help of the Madelung
decomposition approach, the explicit relations between the microscopic and
macroscopic fluid variables are derived. The closed system of equations of
quantum hydrodynamics encompasses the continuity equation, and the dynamical
equations of the momentum balance and the spin density evolution. The possible
experimental manifestations of the torsion in the dynamics of spin waves is
discussed.

9
The categories of this paper are: nlin
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th