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Abstract Gravitational memory effects are predictions of general relativity that are characterized by an observable effect that persists after the passage of gravitational waves. In recent years, they have garnered particular interest, both due to their connection to asymptotic symmetries and soft theorems and because their observation would serve as a unique test of the nonlinear nature of general relativity. Apart from the more commonly known displacement and spin memories, however, there are other memory effects predicted by Einstein’s equations that are associated with more subleading terms in the asymptotic expansion of the Bondi-Sachs metric. In this paper, we write explicit expressions for these higher memory effects in terms of their charge and flux contributions. Further, by using a numerical relativity simulation of a binary black hole merger, we compute the magnitude and morphology of these terms and compare them to those of the displacement and spin memory. We find that, although these terms are interesting from a theoretical perspective, due to their small magnitude they will be particularly challenging to observe with current and future detectors.
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Asymptotic symmetries in Bondi gauge and the sub-subleading soft graviton theorem
We investigate asymptotic symmetries which preserve the Bondi gauge conditions but do not preserve the asymptotic falloff conditions for the metric near the null boundary, and their connection to soft graviton theorems for scattering amplitudes. These include generalized superrotation symmetries parameterized by a smooth vector field $$Y^{A}$$ obeying $$D_{A}Y^{A} = 0$$, for which we show that the associated conserved charge can be derived by applying the Noether procedure to the Einstein–Katz action. We also discuss the connection between asymptotic symmetries and the conserved charge associated with the sub-subleading soft theorem, and we find that in Bondi gauge this charge is generated by the combination of a diffeomorphism together with an extra transformation of the metric.
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- Award ID(s):
- 2210475
- PAR ID:
- 10621213
- Publisher / Repository:
- IOP Publishing Ltd.
- Date Published:
- Journal Name:
- Classical and Quantum Gravity
- Edition / Version:
- 1
- Volume:
- 40
- Issue:
- 23
- ISSN:
- 1361-6382
- Page Range / eLocation ID:
- 235009
- Subject(s) / Keyword(s):
- General relativity Theoretical physics Spacetime symmetries
- Format(s):
- Medium: X Size: 354KB Other: pdf
- Size(s):
- 354KB
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1088/1361-6382/ad0215
