Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Variational Approach to Localization Length for Two-Dimensional Hubbard
  Model
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg