The eikonal exponentiation of gravity amplitudes is a non-perturbative
re- summation whereby certain high-energy divergent terms, which would naively violate unitarity bounds, combine into a harmless phase factor.
Eikonal tech- niques also offer a natural strategy to calculate classical gravitational observables directly from the loop-expansion of scattering amplitudes. In this talk, I will discuss how the eikonal can be applied to obtain the deflection angle for the collision of two non-spinning black holes with generic center-of-mass energies, up to order O(G3). This calculation captures both conservative and dissipa- tive "radiation-reaction" effects, and yields a deflection angle with a smooth behavior at high energies, where it agrees with the universal massless result. Besides explicit two-loop calculations, I will also illustrate a shortcut to access radiation-reaction effects based on analyticity, unitarity and crossing symmetry. Finally, I will sketch how the classical limit of inelastic five-point amplitudes fits in the eikonal exponentiation of elastic four-point amplitudes and provides the leading-order waveforms for the emission of gravitational waves.

Per partecipare in presenza, prenotarsi seguendo il link https://docs.google.com/document/d/1uaw5DHG0VykTHraDiAqYjbLFXsrOIXaftj_n04sj4PE/edit?usp=sharing
oppure per partecipare su Zoom, collegarsi al meeting
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271