Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: "Almost" Quotient Space, Non-dynamical Decoherence and Quantum
  Measurement   An alternative approach to decoherence, named non-dynamical decoherence is
developed and used to resolve the quantum measurement problem. According to
decoherence, the observed system is open to a macroscopic apparatus(together
with a possible added environment) in a quantum measurement process. We show
that this open system can be well described by an "almost" quotient Hilbert
space formed phenomenally according to some stability conditions. A group of
random phase unitary operators is introduced further to obtain an exact
quotient space for the observed system. In this quotient space, a density
matrix can be constructed to give the Born's probability rule, realizing a
(non-dynamical) decoherence. The concept of the ("almost") quotient space can
also be used to explain the classical properties of a macroscopic system. We
show further that the definite outcomes in a quantum measurement are mainly
caused by the "almost" quotient space of the macroscopic apparatus.

9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
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The categories of this paper are: eess
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
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The categories of this paper are: hep-th
23
The categories of this paper are: solv-int