Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: How One Shutter Can Close N Slits   It is shown that a quantum shutter, pre- and post-selected in particular
quantum states, can close simultaneously arbitrary number of slits preventing
the passage of a single photon in an arbitrary state. A set of K pre- and
post-selected shutters can close the slits preventing the passage of K or less
photons. This result indicates that the surprising properties of pre- and
post-selected quantum systems are even more robust than previously expected.

28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics