Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A simple model of quantum trajectories   Quantum trajectory theory, developed largely in the quantum optics community
to describe open quantum systems subjected to continuous monitoring, has
applications in many areas of quantum physics. In this paper I present a simple
model, using two-level quantum systems (q-bits), to illustrate the essential
physics of quantum trajectories and how different monitoring schemes correspond
to different ``unravelings'' of a mixed state master equation. I also comment
briefly on the relationship of the theory to the Consistent Histories formalism
and to spontaneous collapse models.

21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math