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Radiative Asymptotic Symmetries of 3D Einstein-Maxwell Theory

by Jorrit Bosma, Marc Geiller, Sucheta Majumdar, Blagoje Oblak

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Submission summary

Authors (as registered SciPost users): Marc Geiller · Blagoje Oblak
Submission information
Preprint Link:  (pdf)
Date accepted: 2024-03-12
Date submitted: 2024-03-06 12:11
Submitted by: Oblak, Blagoje
Submitted to: SciPost Physics
Ontological classification
Academic field: Physics
  • High-Energy Physics - Theory
Approach: Theoretical


We study the null asymptotic structure of Einstein-Maxwell theory in three-dimensional (3D) spacetimes. Although devoid of bulk gravitational degrees of freedom, the system admits a massless photon and can therefore accommodate electromagnetic radiation. We derive fall-off conditions for the Maxwell field that contain both Coulombic and radiative modes with non-vanishing news. The latter produces non-integrability and fluxes in the asymptotic surface charges, and gives rise to a non-trivial 3D Bondi mass loss formula. The resulting solution space is thus analogous to a dimensional reduction of 4D pure gravity, with the role of gravitational radiation played by its electromagnetic cousin. We use this simplified setup to investigate choices of charge brackets in detail, and compute in particular the recently introduced Koszul bracket. When the latter is applied to Wald-Zoupas charges, which are conserved in the absence of news, it leads to the field-dependent central extension found earlier in [arXiv:1503.00856]. We also consider (Anti-)de Sitter asymptotics to further exhibit the analogy between this model and 4D gravity with leaky boundary conditions.

Author comments upon resubmission

We thank the referees for their positive and enthusiastic comments. We only made a minor change in the conclusion (see details under "list of changes").

List of changes

At the end of the "Perspectives" section, we added a bullet point on supersymmetric extensions following the recommendation of one of the referees. This is accompanied by new references [157-160]. No other change has been made.

Published as SciPost Phys. 16, 092 (2024)

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