High Energy Theory: Tristan McLoughlin

Title: Celestial holography on non-trivial background

Abstract: We will discuss scattering amplitudes on non-trivial electromagnetic and gravitational backgrounds such as shockwaves, conformal primary waves, and conformally soft modes. We will describe the computation of celestial two-point amplitudes on these backgrounds which have the desirable feature that they are not constrained by the kinematic delta-functions of flat space celestial CFT correlators. We will further describe a number of relations between these backgrounds, CFT three-point functions and, by means of the shadow transform, CFT two-point functions. Finally, by comparing celestial amplitudes on electric and magnetic backgrounds, we will provide evidence that the four-dimensional flat-space holographic dual of S-duality in Abelian gauge theory is two-dimensional T-duality.