Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The feasible generation of entangled photon states by using linear
  optical elements   We present a feasible scheme to produce a polarization-entangled photon
states $\frac{1}{\sqrt{2}}(|H>|V>+|V>|H>)$ in a controllable way. This scheme
requires single-photon sources, linear optical elements and photon detectors.
It generates the entanglement of spatially separated photons. The interaction
takes place in the photon detectors. We also show that the same idea can be
used to produce the entangled $N$-photon state
$\frac{1}{\sqrt{2}}(|0,N>+|N,0>)$

37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th