Gravitational soft theorem from emergent soft gauge symmetries
Abstract
We consider and derive the gravitational soft theorem up to the sub-subleading power from the perspective of effective Lagrangians. The emergent soft gauge symmetries of the effective Lagrangian provide a transparent explanation of why soft graviton emission is universal to sub-subleading power, but gauge boson emission is not. They also suggest a physical interpretation of the form of the soft factors in terms of the charges related to the soft transformations and the kinematics of the multipole expansion. The derivation is done directly at Lagrangian level, resulting in an operatorial form of the soft theorems. In order to highlight the differences and similarities of the gauge-theory and gravitational soft theorems, we include an extensive discussion of soft gauge-boson emission from scalar, fermionic and vector matter at subleading power.
Keywords
Cite
@article{arxiv.2110.02969,
title = {Gravitational soft theorem from emergent soft gauge symmetries},
author = {Martin Beneke and Patrick Hager and Robert Szafron},
journal= {arXiv preprint arXiv:2110.02969},
year = {2022}
}
Comments
v2: 48 pages, 5 figures. Added sec. 6.6 discussing loop corrections of the soft theorem. Matches published version