Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stationary states of two-level open quantum systems   A problem of finding stationary states of open quantum systems is addressed.
We focus our attention on a generic type of open system: a qubit coupled to its
environment. We apply the theory of block operator matrices and find stationary
states of two--level open quantum systems under certain conditions applied both
on the qubit and the surrounding.

18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph