The Case Against Smooth Null Infinity and the Persistence of Polyhomogeneity

Explore a comprehensive lecture on the asymptotic behavior of gravitational radiation in the vicinity of spacelike infinity, including past and future null infinity. Delve into a mathematical scattering framework that provides a physical basis for understanding the smoothness of null infinity. Examine a proof sketch demonstrating the irregularity of null infinity in various physically motivated settings, accompanied by a detailed description of the semiglobal asymptotics of gravitational radiation. Investigate the use of asymptotic conservation laws related to Newman-Penrose charges in inferring asymptotics for fixed angular modes. Learn about the persistence of polyhomogeneity and its application in summing individual angular modes. This talk, part of the Thematic Programme on "Carrollian Physics and Holography," is based on joint work with Hamed Masaood and Istvan Kadar.