In this talk, the speaker will review a proof of factorization of the dynamics of infrared gravitons, that uses canonical transformations and is particularly well suited to studying the evolution of local operators in the Heisenberg picture. Working with operators instead of states makes it possible to define Lorentz transformations that commute with infrared gravitons. If these transformations could be promoted to proper unitary transformations on states, they would solve an old “problem” in general relativity, that is the non-uniqueness of the Lorentz group of asymptotically flat spacetime. Canonical transformations can also be defined in a collapse black-hole geometry. They will be used to compute exactly the interaction of Hawking quanta with soft gravitons in the limit that back-reaction on the metric can be neglected.
