Colloquium: Radu Roiban, Penn State

Abstract: Quantum field theory is a common language of many areas of physics. By bringing together aspects of the traditional and formal approaches, modern scattering theory is an important probe of fundamental interactions. After reviewing some of the remarkable properties of scattering amplitudes, we will discuss examples where they played a critical role. They include applications to the general relativistic two-body dynamics and gravitational-wave physics, where they establish the state of the art in weak-field fully relativistic calculations, and the probe of high energy properties of maximally supersymmetric supergravity theory.