Abstract

In recent years, many new techniques have been developed which lead to remarkable insights into perturbative QFT . By-and-large, these techniques have only been applied to the computation of observables on flat backgrounds, so one can legitimately question whether they are robust features of perturbative QFT or just a consequence of the simplicity of Minkowski space. One such technique is the ‘double copy,’ a method for constructing scattering amplitudes in gravity from scattering amplitudes in gauge theory; it even has a catchy slogan, Gravity = (Gauge Theory)^2. In this talk I’ll describe how the robustness of the double copy can be tested by considering scattering on plane wave backgrounds. Although the non-trivial scattering background introduces several subtleties, we’ll see that a notion of double copy persists. Time permitting, I’ll also mention how these new scattering problems can be studied using worldsheet models known as ‘ambitwistor strings.’