# YTF 20

15-16 December 2020
Centre for Particle Theory, Durham
Europe/London timezone

## The Case Against Smooth Null Infinity

16 Dec 2020, 10:30
30m
Teams (Centre for Particle Theory, Durham)

### Teams

#### Centre for Particle Theory, Durham

IPPP & Dept. Mathematical Sciences Durham University South Road Durham DH1 3LE

### Speaker

Leonhard Kehrberger (University of Cambridge)

### Description

In this talk, I hope to discuss various physical obstructions to Penrose's proposal of smooth conformal compactification of spacetime (a.k.a. smooth null infinity or asymptotic simplicity) and the "peeling property" implied by it.
More precisely, I will show that in the context of the $N$-body problem of GR, one should expect that the asymptotic expansions of the Weyl tensor near $\mathcal{I}^+$ contain logarithmic terms at leading order and hence the peeling property does not hold.
Finally, I will outline why these logarithmic terms should in principle be measurable.

Only basic familiarity with GR will be assumed.

Length of talk 15-25 minutes Yes No No

### Primary author

Leonhard Kehrberger (University of Cambridge)

### Presentation Materials

 talkDurham.pdf YTF Day 2 Parallel Stream 3 Leonhard Kehrberger.mp4