Superradiant amplification by stars and black holes

Abstract

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.

References in corpus (11)

• Black Holes at the LHC
• Kerr black holes with scalar hair
• Black-Hole Bombs and Photon-Mass Bounds
• Small Kerr-anti-de Sitter black holes are unstable
• Black Hole Superradiance From Kerr/CFT
• Gravitational signature of Schwarzschild black holes in dynamical Chern-Simons gravity
• Cargese Lectures on the Kerr/CFT Correspondence
• Is there a Supermassive Black Hole at the Center of the Milky Way?
• Astrophysical constraints on Planck scale dissipative phenomena
• Superradiance in stars
• Lagrangian Formalism in Perturbed Nonlinear Klein-Gordon Equations