Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Limits of Information Retrieval in Quantum Mechanics   The widely considered assertion is that the unitarity of quantum mechanical
evolution assures the preservation of information. It is even promoted in
popular literature as an established fact. (Susskind, 2008) Yet, a simple chain
of reasoning demonstrates that: 1) almost any evolutionary operator can be well
approximated by a degenerate (finite-rank) operator and 2) one needs an
eternity to retrieve information exactly from a nonstationary quantum state and
to distinguish between arbitrary unitary operator and its finite-dimensional
approximations.

22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph