Abstract:
While quantum gravity is well understood as an effective field theory when all invariants are sub-Planckian, the super-Planckian (Regge) limit still poses open questions which we are just now starting to address. Naively one might think that such a regime would be sensitive to the UV completion but the semi-classical nature of the process leads to a controlled calculation within GR, at least for massive partons, as a consequence of eikonalization. There have been hints that eikonalization may fail for massless partons, and in this talk I will clarify why we believe this does indeed happen, using effective field theory methods. I will also show how the EFT can expose structures in the perturbative series whose form has yielded new results in the PM expansion.