Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On period, cycles and fixed points of a quantum channel   We consider a quantum channel acting on an infinite dimensional von Neumann
algebra of operators on a separable Hilbert space. When there exists an
invariant normal faithful state, the cyclic properties of such channels are
investigated passing through the decoherence free algebra and the fixed points
domain. Both these spaces are proved to be images of a normal conditional
expectation so that their consequent atomic structure are analyzed in order to
give a better description of the action of the channel and, for instance, of
its Kraus form and invariant densities.

29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin