Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Astrophysical Quantum Matter: Spinless charged particles on a magnetic
  dipole sphere   We consider the quantum mechanics of a spinless charged particle on a
2-dimensional sphere. When threaded with a magnetic monopole field, this is the
well-known Haldane sphere that furnishes a translationally-invariant,
incompressible quantum fluid state of a gas of electrons confined to the
sphere. This letter presents the results of a novel variant of the Haldane
solution where the monopole field is replaced by that of a dipole. We argue
that this system is relevant to the physics on the surface of compact
astrophysical objects like neutron stars.

21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph