Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: mKdV equation approach to zero energy states of graphene   We utilize the relation between soliton solutions of the mKdV and the
combined mKdV-KdV equation and the Dirac equation to construct electrostatic
fields which yield exact zero energy states of graphene.

23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex