Abstract: In this talk I will discuss the relation between Friedrich’s description of spatial infinity and alternative formulations by Ashtekar-Hansen and Ashtekar-Romano. Moreover, I will show how Friedrich’s framework can be used to relate a number of objects defined at null infinity to data on a Cauchy surface. Particular attention will be given to the so-called BMS charges associated to supertranslations in the case of linear fields and the case of the full non-linear GR. Writing the asymptotic charges in terms of initial data allows to establish, in a natural way, the correspondence between charges at future and past null infinity without the need of introduced an ad hoc “antipodal identification”. Moreover, it allows to clarify the required regularity of the solutions for the charges to be well defined and express these regularity requirements in terms of freely specifiable data.

This is work in collaboration with Mariem Magdy Ali Mohammed.

https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09