Black-Hole Scattering, Eikonal Exponentiation and Gravitational Waves

Ottobre 14, 2021@11:00 am–12:00 pm
Aula 603 e online

Seminario di Fisica Teorica INFN/DIFI – Carlo Heissenberg (Nordita, Stockholm, Sweden)
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.

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Topic: Theory and Pheno seminars
Meeting ID: 857 318 5271