Symmetries and charges of general relativity at null boundaries

Abstract We study general relativity at a null boundary using the covariant phase space formalism. We define a covariant phase space and compute the algebra of symmetries at the null boundary by considering the boundary-preserving diffeomorphisms that preserve this phase space. This algebra is the s...

Full description

Bibliographic Details
Main Authors: Venkatesa Chandrasekaran, Éanna É. Flanagan, Kartik Prabhu
Format: Article
Language:English
Published: SpringerOpen 2018-11-01
Series:Journal of High Energy Physics
Subjects:
Online Access:http://link.springer.com/article/10.1007/JHEP11(2018)125
_version_ 1818903964627763200
author Venkatesa Chandrasekaran
Éanna É. Flanagan
Kartik Prabhu
author_facet Venkatesa Chandrasekaran
Éanna É. Flanagan
Kartik Prabhu
author_sort Venkatesa Chandrasekaran
collection DOAJ
description Abstract We study general relativity at a null boundary using the covariant phase space formalism. We define a covariant phase space and compute the algebra of symmetries at the null boundary by considering the boundary-preserving diffeomorphisms that preserve this phase space. This algebra is the semi-direct sum of diffeomorphisms on the two sphere and a nonabelian algebra of supertranslations that has some similarities to supertranslations at null infinity. By using the general prescription developed by Wald and Zoupas, we derive the localized charges of this algebra at cross sections of the null surface as well as the associated fluxes. Our analysis is covariant and applies to general non-stationary null surfaces. We also derive the global charges that generate the symmetries for event horizons, and show that these obey the same algebra as the linearized diffeomorphisms, without any central extension. Our results show that supertranslations play an important role not just at null infinity but at all null boundaries, including non-stationary event horizons. They should facilitate further investigations of whether horizon symmetries and conservation laws in black hole spacetimes play a role in the information loss problem, as suggested by Hawking, Perry, and Strominger.
first_indexed 2024-12-19T20:59:55Z
format Article
id doaj.art-a681a199e11040abadb1583d46f8839e
institution Directory Open Access Journal
issn 1029-8479
language English
last_indexed 2024-12-19T20:59:55Z
publishDate 2018-11-01
publisher SpringerOpen
record_format Article
series Journal of High Energy Physics
spelling doaj.art-a681a199e11040abadb1583d46f8839e2022-12-21T20:05:51ZengSpringerOpenJournal of High Energy Physics1029-84792018-11-0120181116810.1007/JHEP11(2018)125Symmetries and charges of general relativity at null boundariesVenkatesa Chandrasekaran0Éanna É. Flanagan1Kartik Prabhu2Center for Theoretical Physics and Department of Physics, University of CaliforniaDepartment of Physics, Cornell UniversityCornell Laboratory for Accelerator-based Sciences and Education (CLASSE), Cornell UniversityAbstract We study general relativity at a null boundary using the covariant phase space formalism. We define a covariant phase space and compute the algebra of symmetries at the null boundary by considering the boundary-preserving diffeomorphisms that preserve this phase space. This algebra is the semi-direct sum of diffeomorphisms on the two sphere and a nonabelian algebra of supertranslations that has some similarities to supertranslations at null infinity. By using the general prescription developed by Wald and Zoupas, we derive the localized charges of this algebra at cross sections of the null surface as well as the associated fluxes. Our analysis is covariant and applies to general non-stationary null surfaces. We also derive the global charges that generate the symmetries for event horizons, and show that these obey the same algebra as the linearized diffeomorphisms, without any central extension. Our results show that supertranslations play an important role not just at null infinity but at all null boundaries, including non-stationary event horizons. They should facilitate further investigations of whether horizon symmetries and conservation laws in black hole spacetimes play a role in the information loss problem, as suggested by Hawking, Perry, and Strominger.http://link.springer.com/article/10.1007/JHEP11(2018)125Black HolesClassical Theories of GravitySpace-Time Symmetries
spellingShingle Venkatesa Chandrasekaran
Éanna É. Flanagan
Kartik Prabhu
Symmetries and charges of general relativity at null boundaries
Journal of High Energy Physics
Black Holes
Classical Theories of Gravity
Space-Time Symmetries
title Symmetries and charges of general relativity at null boundaries
title_full Symmetries and charges of general relativity at null boundaries
title_fullStr Symmetries and charges of general relativity at null boundaries
title_full_unstemmed Symmetries and charges of general relativity at null boundaries
title_short Symmetries and charges of general relativity at null boundaries
title_sort symmetries and charges of general relativity at null boundaries
topic Black Holes
Classical Theories of Gravity
Space-Time Symmetries
url http://link.springer.com/article/10.1007/JHEP11(2018)125
work_keys_str_mv AT venkatesachandrasekaran symmetriesandchargesofgeneralrelativityatnullboundaries
AT eannaeflanagan symmetriesandchargesofgeneralrelativityatnullboundaries
AT kartikprabhu symmetriesandchargesofgeneralrelativityatnullboundaries