Quasilinear wave equations on asymptotically flat spacetimes with applications to Kerr black holes
4 affiliations
- 1Department of Mathematics, Princeton University, Princeton, NJ, United States, DPMMS, University of Cambridge, Cambridge, United Kingdom
- 2Mathematisches Institut, Fachbereich Mathematik und Informatik der Universität Münster, Münster, Germany
- 3Department of Mathematics, Princeton University, Princeton, NJ, United States
- 4Department of Mathematics, Imperial College London, London, United Kingdom
Abstract
We prove global existence and decay for small-data solutions to a class of quasilinear wave equations on a wide variety of asymptotically flat spacetime backgrounds, allowing in particular for the presence of horizons, ergoregions and trapped null geodesics, and including as a special case the Schwarzschild and very slowly rotating | a | ≪ M Kerr family of black holes in general relativity. There are two distinguishing aspects of our approach. The first aspect is its dyadically localised nature: The nontrivial part of the analysis is reduced entirely to time-translation invariant rp-weighted estimates, in the spirit of [DR09], to be applied on dyadic time-slabs which for large r are outgoing. Global existence and decay then both immediately follow by elementary iteration on consecutive such time-slabs, without further global bootstrap. The second, and more fundamental, aspect is our direct use of a "blackbox" linear inhomogeneous energy estimate on exactly stationary metrics, together with a novel but elementary physical space top order identity that need not capture the structure of trapping and is robust to perturbation. In the specific example of Kerr black holes, the required linear inhomogeneous estimate can then be quoted directly from the literature [DRSR16], while the additional top order physical space identity can be shown easily in many cases (we include in the Appendix a proof for the Kerr case | a | ≪ M, which can in fact be understood in this context simply as a perturbation of Schwarzschild). In particular, the approach circumvents the need either for producing a purely physical space identity capturing trapping or for a careful analysis of the commutation properties of frequency projections with the wave operator of time-dependent metrics.
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BibTeX
@article{dafermos2026quasilinear,
title = {{Quasilinear wave equations on asymptotically flat spacetimes with applications to Kerr black holes}},
author = {Mihalis Dafermos and Gustav H. Holzegel and Igor Rodnianski and Martin Taylor},
journal = {Analysis \& PDE},
year = {2026},
month = may,
doi = {10.2140/apde.2026.19.909},
url = {https://doi.org/10.2140/apde.2026.19.909},
note = {CC BY},
}
RIS
TY - JOUR
TI - Quasilinear wave equations on asymptotically flat spacetimes with applications to Kerr black holes
AU - Mihalis Dafermos
AU - Gustav H. Holzegel
AU - Igor Rodnianski
AU - Martin Taylor
PY - 2026
DA - 2026/05/21
JO - Analysis & PDE
DO - 10.2140/apde.2026.19.909
UR - https://doi.org/10.2140/apde.2026.19.909
AB - We prove global existence and decay for small-data solutions to a class of quasilinear wave equations on a wide variety of asymptotically flat spacetime backgrounds, allowing in particular for the presence of horizons, ergoregions and trapped null geodesics, and including as a special case the Schwarzschild and very slowly rotating | a | ≪ M Kerr family of black holes in general relativity. There are two distinguishing aspects of our approach. The first aspect is its dyadically localised nature: The nontrivial part of the analysis is reduced entirely to time-translation invariant r^p-weighted estimates, in the spirit of [DR09], to be applied on dyadic time-slabs which for large r are outgoing. Global existence and decay then both immediately follow by elementary iteration on consecutive such time-slabs, without further global bootstrap. The second, and more fundamental, aspect is our direct use of a "blackbox" linear inhomogeneous energy estimate on exactly stationary metrics, together with a novel but elementary physical space top order identity that need not capture the structure of trapping and is robust to perturbation. In the specific example of Kerr black holes, the required linear inhomogeneous estimate can then be quoted directly from the literature [DRSR16], while the additional top order physical space identity can be shown easily in many cases (we include in the Appendix a proof for the Kerr case | a | ≪ M, which can in fact be understood in this context simply as a perturbation of Schwarzschild). In particular, the approach circumvents the need either for producing a purely physical space identity capturing trapping or for a careful analysis of the commutation properties of frequency projections with the wave operator of time-dependent metrics.
SN - 1948-206X
SN - 2157-5045
ER -