Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Piezoelectric and optical setup to measure an electrical field:
  Application to the longitudinal near-field generated by a tapered coax
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin