Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Entanglement and reduction in two-photon correlations   For a number of basic experiments on two-photon intensity correlations it is
pointed out that the results, which are usually explained in terms of the
formalism of canonical field quantization, can also be explained in terms of
quantum wave packets, where reduction and entanglement are taken into account.

4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ