ETD

• Hawking Radiation
• Scattering Amplitudes

Recent advances in the amplitudes program have demonstrated the efficacy of on-shell scattering techniques in computing not only classical gravitational observables but also semiclassical phenomena. Notably, the Hawking spectrum of a Schwarzschild black hole can be recovered by exponentiating a series of tree-level Feynman diagrams on a Vaidya collapse background, a framework where Bogoliubov coefficients are naturally reinterpreted as generalised in-in expectation values. This thesis extends this novel formalism to the case of charged black holes. By modeling the collapse via a Vaidya-Bonner metric, we apply (semi-)classical amplitude methods to compute the scattering of a massless scalar field. We investigate how the introduction of electric charge, which alters the causal structure of spacetime and adds a new term to the scattering potential, modifies the eikonal-like resummation. Finally, we compare the scattering results with the standard geometric-optics derivation of Hawking radiation for a Reissner-Nordström black hole, analyzing the validity regime of current amplitude techniques in capturing horizon-scale finite-size effects induced by the charge.