Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Damping of low-energy excitations of a Bose-condensed gas in the
  hydrodynamic regime   We develop a theory to describe the damping of elementary excitations of a
Bose-condensed gas in the hydrodynamic regime for the thermal cloud. We discuss
second sound in a spatially homogeneous gas and the lowest excitations of a
trapped condensate.

30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin