Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Finite temperature hydrodynamic modes of trapped quantum gases   The hydrodynamic equations of an ideal fluid formed by a dilute quantum gas
in a parabolic trapping potential are studied analytically and numerically. Due
to the appearance of internal modes in the fluid stratified by the trapping
potential, the spectrum of low-lying modes is found to be dense in the
high-temperature limit, with an infinitely degenerate set of zero-frequency
modes. The spectrum for Bose-fluids and Fermi-fluids is obtained and discussed.

31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ