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Stable radiation-controlling boundary conditions for the generalized harmonic Einstein equations

Oliver Rinne
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Abstract

This paper is concerned with the initial-boundary value problem for the Einstein equations in a first-order generalized harmonic formulation. We impose boundary conditions that preserve the constraints and control the incoming gravitational radiation by prescribing data for the incoming fields of the Weyl tensor. High-frequency perturbations about any given spacetime (including a shift vector with subluminal normal component) are analyzed using the Fourier-Laplace technique. We show that the system is boundary-stable. In addition, we develop a criterion that can be used to detect weak instabilities with polynomial time dependence, and we show that our system does not suffer from such instabilities. A numerical robust stability test supports our claim that the initial-boundary value problem is most likely to be well-posed even if nonzero initial and source data are included.

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Oliver Rinne. 2006-09-06. Stable radiation-controlling boundary conditions for the generalized harmonic Einstein equations. https://doi.org/10.1088/0264-9381%2F23%2F22%2F013

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