The Case Against Smooth Null Infinity and the Persistence of Polyhomogeneity

17.04.2024 14:15 - 15:45

Leonhard Kehrberger, University of Leipzig


In this talk, I will describe recent and upcoming work on the asymptotic behaviour of gravitational radiation (linearised gravity around Schwarzschild) in a neighbourhood of spacelike infinity including past and future null infinity. I will first set up a mathematical scattering framework in which one can understand the question of smoothness of null infinity on physical grounds. I will then use this framework to present a basic sketch of the proof of the irregularity of null infinity in various physically motivated settings, together with a complete description of the semiglobal asymptotics of gravitational radiation one obtains instead.
In particular, I will discuss how a class of asymptotic conservation laws related to the Newman-Penrose charges can be used to infer the asymptotics for fixed angular modes, and describe how to use a persistence of polyhomogeneity result to sum up the individual angular modes.

Based on joint work with Hamed Masaood and Istvan Kadar.

P. Chrusciel, D. Fajman

Fakt. f. Physik, SR A, 2. Stock, Währingerstr. 17, 1090 Wien