Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Spontaneous Parametric Down-Conversion Experiment to Measure Both Photon
  Trajectories and Double-Slit Interference
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph