The Next-to-Leading Order Scattering Waveform from Amplitudes

I will showcase the computation of the next-to-leading order scattering waveform in classical gravity using amplitude techniques. I will first give an overview of how to compute generic classical observables in gravity using scattering amplitude techniques in the KMOC formalism. In particular, I will focus on how classical physics systematically emerges from quantum amplitudes and how calculations simplify in the classical limit. I will then sketch the computation of the sub-leading contribution to the classical waveform, an out-of-time-order observable which roughly corresponds to the 1-loop 5-point amplitude. I will conclude with a discussion of different aspects of the waveform, such as the memory effect and an IR divergent phase, along with future directions.