2023/02/17(Fri)
11:00 -12:00
五樓第一會議室 5F, 1st Meeting Room
視訊演講 Video Seminar [ Meeting Link / ID: 2513 419 1834 / Password: FridaySeminar23 ]
Title
Two approaches to (3D) free hyperboloidal evolution
Speaker
Dr. Alex Vañó-Viñuales (CENTRA, University of Lisbon)Abstract
Gravitational wave radiation, our window for probing the strong field and dynamical regime of gravity, is unambiguously defined only at future infinity - the location in spacetime where light rays arrive and thus where signals and global properties of spacetimes can be measured. A convenient way to include it in numerical relativity simulations is using hyperboloidal foliations, which consist of smooth spacelike slices that reach future null infinity. I will review the current state of the art of two suitable free-evolution approaches. The first one uses conformal compactification, based on an idea by Nobel-laureate Roger Penrose, and is implemented via the BSSN and Z4 formulations of the Einstein equations. It has provided very promising spherically symmetric numerical evolutions of a massless scalar field coupled to gravity, which I will show. The second approach employs the dual-frame method to preserve the well-posedness of the Generalized Harmonic Gauge formulation while using coordinates adapted to the hyperboloidal slices. Its preliminary results in spherical symmetry also show the potential of this approach. Finally, I will give an update on current ongoing work towards 3D evolution, as the final goal of this work is to provide a far-field numerical framework that includes null infinity for simulations of compact object mergers with accurate gravitational wave extraction.
Language
演講語言 (Language): in English
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