Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superradiant amplification by stars and black holes   In this thesis we study the phenomenon of superradiance and its implications
to the stability of black-holes (BH) and perfect-fluid stars.
  Superradiance is a radiation enhancement process that involves rotating
dissipative systems. In BH spacetimes, superradiance is due to dissipation at
the event horizon, with interesting associated phenomena, namely floating
orbits and BH-bombs. BH superradiance is a very interdisciplinary topic, and
its study allows us to obtain important results in the area of particle
physics. The scattering of a scalar field by a rotating BH leads to the
formation of quasi-boundstates. In rotational systems, these states can give
rise to superradiant instabilities. These results were recently used to impose
constraints to the mass of fundamental particles and darkmatter candidates.
  In this work, it is shown that, when dissipation is properly included,
similar results are achievable in self-gravitating systems other than
black-holes, such as perfect fluid stars. It is also demonstrated that the
relativistic effects related to the phenomenon of frame-dragging are
neglectable in this calculation.

15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas