Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unification of Dark Energy and Dark Matter   We propose a scenario in which dark energy and dark matter are described in a
unified manner. The ultralight pseudo-Nambu-Goldstone (pNG) boson, A, naturally
explains the observed magnitude of dark energy, while the bosonic supersymmetry
partner of the pNG boson, B, can be a dominant component of dark matter. The
decay of B into a pair of electron and positron may explain the 511 keV gamma
ray from the Galactic Center.

37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph