Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quadrupole interaction of relativistic quantum particle with external
  fields   We consider the motion of a spinning relativistic particle with an arbitrary
value of spin in external electromagnetic and gravitational fields, to first
order in the external field. We use the noncovariant description of spin. An
explicit expression is obtained for the interaction of second order in spin.
The value of the quadrupole moment is found for which this interaction
decreases when the energy grows.

17
The categories of this paper are: q-fin
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The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
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The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
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The categories of this paper are: stat
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The categories of this paper are: econ
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol