Séminaire / Seminar GReCO |
| « Evolve the Frame, Resolve the Memory: The Bondi–Sachs Gauge in Black Hole Perturbation Theory » |
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Andrew Spiers |
| Self-force models are a burgeoning method for calculating black hole binary waveforms. Understanding gauge and frame dependence is crucial for making calculations tractable, comparing binary models, and extracting physical observables. Black hole perturbation theory self-force calculations are extending to second order, where increased gauge dependence introduces new challenges: gauge-invariant quantities at linear order become gauge-dependent at second order, and nonlinear source terms can produce infrared divergences. Additionally, gravitational wave memory, a frame-dependent effect detectable with next-generation detectors, appears at second order. In this talk, I briefly review second-order black hole perturbation theory, self-force modelling, the Bondi–Sachs gauge, the BMS frame, and memory effects; by combining these elements, I construct a gauge-invariant second-order field equation associated with an asymptotically flat gauge with the appropriate frame to extract the memory from self-force models. |
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lundi 19 octobre 2026 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |