Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Observation of long-lived polariton states in semiconductor
  microcavities across the parametric threshold
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con