Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Simultaneous Measurement of Non-commuting Observables and Quantum
  Fractals on Complex Projective Spaces   Simultaneous measurement of several noncommuting observables is modeled by
using semigroups of completely positive maps on an algebra with a non-trivial
center. The resulting piecewise-deterministic dynamics leads to chaos and to
nonlinear iterated function systems (quantum fractals) on complex projective
spaces.

25
The categories of this paper are: patt-sol
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
19
The categories of this paper are: eess
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
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