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Charges in the Extended BMS Algebra: Definitions and Applications

by M. Porrati

Submission summary

As Contributors: Massimo Porrati
Preprint link: scipost_202012_00003v1
Date accepted: 2021-01-29
Date submitted: 2020-12-02 07:17
Submitted by: Porrati, Massimo
Submitted to: SciPost Physics Proceedings
Proceedings issue: PSI Particle Physics
Academic field: Physics
  • High-Energy Physics - Theory
Approach: Theoretical


This is a review of selected topics from recent work on symmetry charges in asymptotically flat spacetime done by the author in collaboration with U. Kol and R. Javadinezhad. First we reinterpret the reality constraint on the boundary graviton as the gauge fixing of a new local symmetry, called dual supertranslations. This symmetry extends the BMS group and bears many similarities to the dual (magnetic) gauge symmetry of electrodynamics. We use this new gauge symmetry to propose a new description of the TAUB-NUT space that does not contain closed time-like curves. Next we summarize progress towards the definition of Lorentz and super-Lorentz charges that commute with supertranslations and with the soft graviton mode.

Current status:
Publication decision taken: accept

Editorial decision: For Journal SciPost Physics Proceedings: Publish
(status: Editorial decision fixed and (if required) accepted by authors)

Author comments upon resubmission

Clarifications after eq. (7) and (13) on the definition and meaning of gauge charges.
The limit due to the new gauge symmetry being defined only asymptotically is made more explicit in the third bullet point after (13)

List of changes

Clarifications after eq. (7) and (13) on the definition and meaning of gauge charges and observables.

Submission & Refereeing History

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Resubmission scipost_202012_00003v1 on 2 December 2020

Reports on this Submission

Anonymous Report 1 on 2021-1-14 Invited Report


One of the requested changes (boundary conditions necessary for the existence of topological charges) has been addressed. The request for a physical explanation of the complex gauge transformation in real terms (especially for an observer) has not been addressed. As explained in the first report, the proceedings is clearly written. Since the authors plans on submitting a further paper on the topic, the unaddressed suggestions can be kept for further research. This proceedings summarizes past research by the author.

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