Scattering Amplitudes on the Celestial sphere

Abstract: The identification of quantum field theoretic soft theorems with constraints from infinite-dimensional asymptotic symmetries offers exciting prospects for solving the scattering problem in quantum gravity. In four spacetime dimensions, the asymptotic symmetry group includes the local conformal (Virasoro) symmetry of two dimensions, motivating the proposal that 4D scattering is holographically dual to a 2D conformal theory. Lorentz symmetry in four dimensions comprises the global part of the 2D conformal group of the dual. Asymptotic particles in boost as opposed to standard momentum eigenstates transform like primary operators, and thereby manifestly exhibit the underlying conformal symmetry. Scattering amplitudes for such states -- known as celestial amplitudes -- involve contributions from asymptotic particles of arbitrarily high energy and accordingly do not respect the familiar paradigm of Wilsonian IR/UV decoupling. Nevertheless, I will describe how various observable IR and UV phenomena can be canonically extracted directly from celestial amplitudes. Moreover, a manifestly Lorentz covariant formulation of scattering constraints is necessary for their direct application to celestial amplitudes. I will explain how constraints from Poincare symmetry, soft UV behavior of quantum gravity, and asymptotic symmetries are covariantly implemented in celestial amplitudes.

HEP - theory

Audience: researchers in the topic

SISSA HEP seminars

Series comments: Description: Research seminars on theoretical high energy physics

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