Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Bulk viscosity and the conformal anomaly in the pion gas
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
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
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph