Routing protocol

Physics

Computer network

Mathematics

Black hole (networking)

Link-state routing protocol

Infinitesimal

Statistical physics

Astronomy

Horizon

Mathematical analysis

Einstein

Event horizon

Power (physics)

Gravitational wave

Theoretical physics

Computer science

Quantum mechanics

Generator (circuit theory)

Routing (electronic design automation)

Binary black hole

Binary number

Classical mechanics

Arithmetic

Classical and Quantum Gravity

The merger phase of binary black hole coalescences is a transient between an initial oscillating regime (inspiral) and a late exponentially damped phase (ringdown). In spite of the non-linear character of Einstein equations, the merger dynamics presents a surprisingly simple behaviour consistent with effective linearity. On the other hand, energy loss through the event horizon and by scattering to infinity renders the system non-conservative. Hence, the infinitesimal generator of the (effective) linear dynamics is a non-selfadjoint operator. Qualitative features of transients in linear dynamics driven by non-selfadjoint (in general, non-normal) operators are captured by the pseudospectrum of the time generator. We propose the pseudospectrum as a unifying framework to thread together the phases of binary black hole coalescences, from the inspiral-merger transition up to the late quasinormal mode ringdown.

Pseudospectrum and binary black hole merger transients