Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Density Matrix Formalism for PT-Symmetric Non-Hermitian Hamiltonians
  with the Lindblad Equation
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
1
The categories of this paper are: cs
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph