Already for the linear wave equation on the Minkowski spacetime, scattering solutions arising from data in the infinite past (at "past null infinity") have surprisingly different asymptotic behaviour towards future null infinity depending on both the dimension and on the nature of the scattering data.
In this talk, I will explain and prove these differences, and I will then sketch how to more generally determine the asymptotics towards future null infinity for a much wider class of quasilinear equations.
In the context of the Einstein equations of general relativity, this work allows to determine the asymptotics of gravitational radiation, and thus the smoothness of null infinity, in physically realistic scattering scenarios.
Based on joint work with Istvan Kadar (Princeton University)