PIRSA:24030114

Video URL

https://pirsa.org/24030114

Loop corrected subleading soft graviton theorem from anomalous BRST Ward identity

Wetzstein, T. (2024). Loop corrected subleading soft graviton theorem from anomalous BRST Ward identity . Perimeter Institute for Theoretical Physics. https://pirsa.org/24030114

Wetzstein, Tom. Loop corrected subleading soft graviton theorem from anomalous BRST Ward identity . Perimeter Institute for Theoretical Physics, Mar. 14, 2024, https://pirsa.org/24030114 

          @misc{ scivideos_PIRSA:24030114,
            doi = {10.48660/24030114},
            url = {https://pirsa.org/24030114},
            author = {Wetzstein, Tom},
            keywords = {Quantum Gravity},
            language = {en},
            title = {Loop corrected subleading soft graviton theorem from anomalous BRST Ward identity },
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2024},
            month = {mar},
            note = {PIRSA:24030114 see, \url{https://scivideos.org/pirsa/24030114}}
          }

Tom Wetzstein Laboratory of Theoretical and High Energy Physics

Talk numberPIRSA:24030114
DOI10.48660/24030114
Source RepositoryPIRSA
Collection
Talk Type Scientific Series
Subject

Abstract

Extended BMS symmetry is believed to be a fundamental symmetry of any classical gravitational scattering process, as well as of the quantum gravity S-matrix. We explore this property using the BRST formulation of BMS symmetry, which allows to construct a non trivial solution of the Wess-Zumino consistency condition at the null boundaries of spacetime. We interpret this solution as an anomaly for asymptotic BRST Ward identities for superrotations. By relating them to the leading and subleading soft graviton theorem, we recover the well known results that the leading soft theorem is exact at all loop in perturbation theory without ever referring to Feynman diagrams, while the anomaly for superrotations is at the origin of the 1-loop correction to the subleading soft factor. This construction provides a rigorous, fully quantum origin for the invariance of the S-matrix under asymptotic symmetries.

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