Alfredo Guevara (Physics) - BHI
Title: Black Holes, Scattering Amplitudes and Twistors
Abstract: Scattering amplitudes are very natural in (2,2) signature, where the on-shell three-point functions do not vanish. Motivated by recent progress in celestial holography, we link (2,2) scattering amplitudes to Black Holes in (2,2) Klein space, and study their global structure. The link is very natural from the perspective of twistor theory. These black holes are a simple analytic continuation away from (1,3) solutions, but their (2,2) signature unveils new properties such as a direct diffeomorphism between Kerr Taub-NUT and Taub-NUt spacetimes.
Bio: Alfredo is a Junior Fellow at the Harvard Society of Fellows. His research lies at the crossroads between quantum theory and classical gravity. In particular, he is adapting novel techniques from the S-Matrix program to the study of classical solutions in general relativity such as those describing spinning black holes, a correspondence that also sheds light on the puzzle of higher-spin particles. He is currently interested in observational signatures of these classical processes, which may be measured via gravitational waves such as the ones to be detected by LIGO/LISA, but also through electromagnetic radiation. Furthermore, he is studying the asymptotic structure of spacetime and its connection to the infrared problem of quantum theory, as well as novel geometrical structures underlying scattering amplitudes in a variety of theories.