Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A "Garden of Forking Paths" - the Quantum Mechanics of Histories of
  Events   We present a short survey of a novel approach, called "ETH approach", to the
quantum theory of events happening in isolated physical systems and to the
effective time evolution of states of systems featuring events. In particular,
we attempt to present a clear explanation of what is meant by an "event" in
quantum mechanics and of the significance of this notion. We then outline a
theory of direct (projective) and indirect observations or recordings of
physical quantities and events. Some key ideas underlying our general theory
are illustrated by studying a simple quantum-mechanical model of a mesoscopic
system.

35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
2
The categories of this paper are: math