Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Multiple fluxon analogues and dark solitons in linearly coupled
  Bose-Einstein condensates   Two effectively one-dimensional parallel coupled Bose-Einstein condensates in
the presence of external potentials are studied. The system is modelled by
linearly coupled Gross-Pitaevskii equations. In particular, the interactions of
grey-soliton-like solutions representing analogues of superconducting Josephson
fluxons as well as coupled dark solitons are discussed. A theoretical
approximation based on variational formulations to calculate the oscillation
frequency of the grey-soliton-like solution is derived and a qualitatively good
agreement is obtained.

5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom