1:30 pm VIA ZOOM
A Symmetry-Based Perspective on Soft Factorization in Gravity, Monica Pate, Harvard
The identification of symmetry as the origin of universal behavior in the infrared provides a novel perspective on the structure of scattering in theories of gauge and gravity. I will explain how this general paradigm applies to the factorization of gravitational scattering amplitudes into universal infrared-divergent (soft) pieces and infinite-finite (hard) parts. In particular, the infrared divergent component is fully captured by a correlation function of two boundary currents, which live on the celestial sphere. The first of these is the supertranslation current, which generates spacetime supertranslations. The second is its symplectic partner, which can be identified as the Goldstone current for spontaneously broken supertranslations. Finally, I will describe how gravitational memory, which is an infrared-safe observable, can be extracted from the soft part of the gravitational scattering amplitude.