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arXiv · 1712.03211

BMS symmetry, soft particles and memory

Atreya Chatterjee·David A. Lowe
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Abstract

In this work, we revisit unitary irreducible representations of the Bondi-Metzner-Sachs (BMS) group discovered by McCarthy. Representations are labelled by an infinite number of super-momenta in addition to four-momentum. Tensor products of these irreducible representations lead to particle-like states dressed by soft gravitational modes. Conservation of 4-momentum and supermomentum in the scattering of such states leads to a memory effect encoded in the outgoing soft modes. We note there exist irreducible representations corresponding to soft states with strictly vanishing four-momentum, which may nevertheless be produced by scattering of particle-like states. This fact has interesting implications for the S-matrix in gravitational theories.

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Atreya Chatterjee, David A. Lowe. 2017-12-08. BMS symmetry, soft particles and memory. https://doi.org/10.1088/1361-6382%2Faab5cc

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