Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Negative differential conductivity in Heisenberg XXZ chain far from
  equilibrium
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg