Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum diffraction and interference of spatially correlated photon
  pairs generated by spontaneous parametric down-conversion   We demonstrate one- and two-photon diffraction and interference experiments
utilizing parametric down-converted photon pairs (biphotons) and a transmission
grating. With two-photon detection, the biphoton exhibits a
diffraction-interference pattern equivalent to that of an effective single
particle that is associated with half the wavelength of the constituent
photons. With one-photon detection, however no diffraction-interference pattern
is observed. We show that these phenomena originate from the spatial quantum
correlation between the down-converted photons.

27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat