Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Hexagonal Plaquette Spin-spin Interactions and Quantum Magnetism in a
  Two-dimensional Ion Crystal
16
The categories of this paper are: stat
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga