High Energy Theory Seminar

Soft theorems relate scattering amplitudes involving extremely low-energy massless particles to those without them. Such relations have played an important role in the amplitudes program and also secretly encode infinite-dimensional symmetry algebras called asymptotic symmetries. Moreover, certain soft theorems are universal; i.e. the first two terms in the low-energy expansion for soft gravitons have explicit relations which apply in all theories of gravity agnostic of the specific details.

While soft theorems in supersymmetric theories have a rich history, they have only been chronicled for a small number of specific examples (think N = 8 SUGRA) due to the fact that they are often derived with pages of technical Feynman diagrammatics. By contrast, I will show that in supersymmetric theories, knowing the soft theorem for a single particle in a supermultiplet allows one to immediately determine soft theorems for the remainder of the supermultiplet in one line of algebra. Such simplicity sheds light on how soft theorems are deeply constrained by the underlying symmetries of a theory more generally. Time permitting, I will discuss the connection to asymptotic symmetries in the supersymmetric setting, arguing that the bms_4 algebra of gravity in asymptotically flat spacetime gets extended to a novel sbms_{4|N} algebra. Based on: 2404.03717 and 2412.13113.

The talk is in 469 Lauritsen.

Contact theoryinfo@caltech.edu for Zoom information.