Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quasinormal modes, Superradiance and Area Spectrum for 2+1 Acoustic
  Black Holes   We present an exact expression for the quasinormal modes of acoustic
disturbances in a rotating 2+1 dimensional sonic black hole (draining bathtub
fluid flow) in the low frequency limit and evaluate the adiabatic invariant
proposed by Kunstatter. We also compute,via Bohr-Sommerfeld quantization rule
the equivalent area spectrum for this acoustic black hole, and we compute the
superradiance phenomena for pure spinning 2+1 black holes.

34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph