From an October 2017 homepage:
Nima Arkani-Hamed1 of the Institute for Advanced Studies in Princeton, with a sweeping naturalness, proclaims “Spacetime is doomed”2 (go to 5:45 minutes of 1.22.44). Pacing throughout3, his really-real reality is within his ever-so-illusive amplituhedron4 with a string to a planar N.5 He declares that it’s equal to the perturbative topological B-model string theory in twistor space6 (an ever-so-positive Grassmannian7) (related ArXiv article).
To which I reply, “Yes, of course. We knew that.”
1 The first link goes to our correspondence (mostly emails) to Nima Arkani-Hamed. He has also received a few tweets as well.
2 Spacetime is doomed is a YouTube video. If you go to 5:45 minutes of his 1 hour 22 minute lecture, you will hear that indeed, spacetime is doomed. The entire lecture is his focus on this concept.
3 Pace-Man is our affectionate name for Nima, from his pacing back and forth when he gives a lecture.
4 The amplituhedron has a special place within our work. It was one of many basic structures and by no means is the most basic. The transformations between circles and spheres to lines and tetrahedra and then octahedra are.
We knew that:
5 The N=4 supersymmetric Yang–Mills theory within Wikipedia is entirely readable, but not easily understood.