Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Optical coherence of Er$^{3+}$:Y$_2$O$_3$ ceramics for telecommunication
  quantum technologies
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat