Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Multi-photon, multi-mode polarization entanglement in parametric
  down-conversion   We study the quantum properties of the polarization of the light produced in
type II spontaneous parametric down-conversion in the framework of a multi-mode
model valid in any gain regime. We show that the the microscopic polarization
entanglement of photon pairs survives in the high gain regime (multi-photon
regime), in the form of nonclassical correlation of all the Stokes operators
describing polarization degrees of freedom.

4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg