Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A New Mechanism of Open System Evolution and Its Entropy Using Unitary
  Transformations in Noncomposite Qudit Systems   The evolution of an open system is usually associated with the interaction of
the system with an environment. A new method to study the open-type system
evolution of a qubit (two-level atom) state is established. This evolution is
determined by a unitary transformation applied to the qutrit (three-level atom)
state, which defines the qubit subsystems. This procedure can be used to obtain
different qubit quantum channels employing unitary transformations into the
qutrit system. In particular, we study the phase damping and
spontaneous-emission quantum channels. In addition, we mention a proposal for
quasiunitary transforms of qubits, in view of the unitary transform of the
total qutrit system. The experimental realization is also addressed. The
probability representation of the evolution and its information-entropic
characteristics are considered.

18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex