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arXiv · 2603.06297

Infrared physics of QED and gravity from representation theory

Laura Donnay·Yannick Herfray
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Abstract

The infrared structure of QED and gravity is known to be governed by an infinite-dimensional symmetry group which extends the Poincar\'e group to include, respectively, large $U(1)$ transformations and BMS supertranslations. We describe how the unitary irreducible representations (UIRs) of these asymptotic symmetry groups encode universal infrared features of a scattering process. Motivated by the goal of defining an infrared-finite $S$-matrix based on these UIRs, we also study supermomentum eigenstates and contrast our construction with the dressed-state approach for infrared-safe amplitudes.

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Laura Donnay, Yannick Herfray. 2026-03-06. Infrared physics of QED and gravity from representation theory. https://arxiv.org/abs/2603.06297

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