From Scattering to the Dynamics of Black Holes and Fluids

The S-matrix bootstrap is a systematic framework for deriving dynamics without reference to an action or an underlying spacetime.  Remarkably, the expressions gleaned from this line of attack are marvelously simple, revealing new structures long hidden in plain sight.  As examples, I describe the duality between color and kinematics and how gravity serves as the "mother of all theories" whose S-matrix secretly encodes and unifies those of gluons, pions, and Galileons.  I then describe recent progress applying these ideas to subjects somewhat less well-tread by particle physicists: gravitational wave physics and fluid dynamics.  First, I discuss how cutting edge ideas from amplitudes have been fused with classic tools from effective field theory to derive state-of-the-art results on the orbital dynamics of binary black holes and neutron stars.  Second, I show how the Navier-Stokes equation encodes scattering amplitudes of fluid quanta which are also amenable to amplitudes analysis and exhibit a litany of familiar structures, including soft theorems, recursion, and the double copy.

Recording available at: https://mediaspace.epfl.ch/channel/High+Energy+Theory+Seminars/32518