Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Light scattering from stationary $\mathcal{PT}$-symmetric collections of
  particles   A potential scattering theory from deterministic and random $\mathcal{PT}$
collections of particles with gain and loss is introduced and the forms of
their structure and pair-structure factors are elucidated. An example relating
to light scattering from a random distribution of a pair of particles with gain
and loss is considered.

18
The categories of this paper are: econ
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th