素粒子論セミナーのお知らせ

Recently, there has been growing attention to applying quantum field-theoretic techniques, such as scattering amplitudes, to problems of classical gravity. In this talk, we push forward this program to understand the physics of black holes, especially their horizons, at both classical and quantum levels. Central to this is the mass-changing amplitude, where a black hole transitions to a different mass state by absorption or emission. We discuss that this amplitude correctly describes mergers of two black holes, horizon absorption of gravitational waves, and Hawking radiation. This perspective can be further extended to a generic macroscopic object with degenerate internal states, allowing us to investigate non-equilibrium transitions between asymptotic equilibrium states by using scattering amplitudes.