w(1+infinity) in 4D Gravity
In this talk, I will show that the action of soft graviton operators generates a w(1+infinity) symmetry in gravitational theories minimally coupled to massless and massive scalar matter in 4D asymptotically flat spacetimes. I will discuss how the symmetry action follows from an infinite tower of soft graviton theorems in momentum space. By generalizing the previous analyses of w(1+infinity) symmetry in massless amplitudes, these results clarify that the symmetry emerges in 4D asymptotically flat gravitational theories without any additional technical ingredients. This talk is based on a forthcoming paper with Monica Pate.