Superradiance without event horizons in General Relativity
General Relativity and Quantum Cosmology
2013-08-07 v2
Abstract
Superradiant scattering processes are studied in general relativistic systems which, unlike rotating and/or charged black holes, do not exhibit an event horizon. Inspired by Zel'dovich's seminal works on the amplification of waves by a rotating cylinder, we analyse, in the context of General Relativity, the possibility of superradiance for electromagnetic waves reflecting off a rotating star and for charged scalar perturbations impinging on a charged sphere. The role of energy dissipation in these systems is analysed and compared with the role of the event horizon in black hole superradiance.
Cite
@article{arxiv.1306.3137,
title = {Superradiance without event horizons in General Relativity},
author = {Maurício Richartz and Alberto Saa},
journal= {arXiv preprint arXiv:1306.3137},
year = {2013}
}
Comments
5 pages; typos corrected; revised assumptions and revised argument in section II, results unchanged