Isolated systems, asymptotics and the structures on null-infinity

Waves, gravitation and geometry

The seminar will meet in Jingzhai (静斋) 105, Tsinghua University. In this seminar, we will study wave equations particularly nonlinear wave equations, from a geometric perspective, and inspired by the dynamics in general relativity. Among the topics ofinterest are black holes, stability, long-term dynamics,low-regularity, fluids, and shocks. We will have a combination of external and local speakers, including students.

Organizer：

Lars Andersson

Speaker：

Jörg Frauendiener (University of Otago)

Time：

Wed., 10:15 am-12:00 pm, Mar. 12, 2025

Venue：

Jingzhai 105

Online：

Zoom Meeting ID:518 868 7656

Password: BIMSA

Title：

Isolated systems, asymptotics and the structures on null-infinity

Abstract：

The idea of an isolated system is fundamental in physics, particularly in GR. Mathematically, it is realised as an asymptotically flat space-time. Penrose's geometric insights allow us to conformally compactify such a space-time by introducing a conformal boundary called null-infinity. It is a null hypersurface which inherits many properties of Minkowski space and on which the non-linear fields of the space-time leave many interesting "imprints”. In this series of talks, I will discuss the foundations of null-infinity, introduce the structures thereon and point to open problems.