The physics of black hole binaries: geodesics, relaxation modes and energy extraction. (arXiv:1905.05204v1 [gr-qc])
<a href="http://arxiv.org/find/gr-qc/1/au:+Bernard_L/0/1/0/all/0/1">Laura Bernard</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Cardoso_V/0/1/0/all/0/1">Vitor Cardoso</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Ikeda_T/0/1/0/all/0/1">Taishi Ikeda</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Zilhao_M/0/1/0/all/0/1">Miguel Zilhao</a>
Black holes are the simplest macroscopic objects, and provide unique tests of
General Relativity. They have been compared to the Hydrogen atom in quantum
mechanics. Here, we establish a few facts about the simplest systems bound by
gravity: black hole binaries. We provide strong evidence for the existence of
`global’ photosurfaces surrounding the binary, and of binary quasinormal modes
leading to exponential decay of massless fields when the binary spacetime is
slightly perturbed. These two properties go hand in hand, as they did for
isolated black holes. The binary quasinormal modes have high quality factor and
may be prone to resonant excitations. Finally, we show that energy extraction
from binaries is generic and we find evidence of a new mechanism — akin to the
Fermi acceleration process — whereby the binary transfers energy to its
surroundings in a cascading process. The mechanism is conjectured to work when
the individual components spin, or are made of compact stars.
Black holes are the simplest macroscopic objects, and provide unique tests of
General Relativity. They have been compared to the Hydrogen atom in quantum
mechanics. Here, we establish a few facts about the simplest systems bound by
gravity: black hole binaries. We provide strong evidence for the existence of
`global’ photosurfaces surrounding the binary, and of binary quasinormal modes
leading to exponential decay of massless fields when the binary spacetime is
slightly perturbed. These two properties go hand in hand, as they did for
isolated black holes. The binary quasinormal modes have high quality factor and
may be prone to resonant excitations. Finally, we show that energy extraction
from binaries is generic and we find evidence of a new mechanism — akin to the
Fermi acceleration process — whereby the binary transfers energy to its
surroundings in a cascading process. The mechanism is conjectured to work when
the individual components spin, or are made of compact stars.
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