# On asymptotic symmetries and subleading soft graviton theorem

**Authors:** Miguel Campiglia, Alok Laddha  
**arXiv:** [1408.2228](https://arxiv.org/abs/1408.2228)  
**Date:** 2014-08-10  
**Summary page:** https://www.summarizepaper.com/fr/paper/1408.2228v1/

## Abstract

Motivated by the equivalence between soft graviton theorem and Ward identities for the supertranslation symmetries belonging to the BMS group, we propose a new extension (different from the so-called extended BMS) of the BMS group which is a semi-direct product of supertranslations and Diff(S^2). We propose a definition for the canonical generators associated to the smooth diffeomorphisms and show that the resulting Ward identities are equivalent to the subleading soft graviton theorem of Cachazo and Strominger.