Double soft graviton theorems and Bondi-Metzner-Sachs symmetries

Asymptotic symmetries of gauge theories are known to encode infrared properties of radiative fields. In the context of tree-level Yang-Mills theory, the leading soft behavior of gluons is captured by large gauge symmetries with parameters that are O(1) in the large r expansion towards null infinity. This relation can be extended to subleading order provided one allows for large gauge symmetries with O(r) gauge parameters. The latter, however, violate standard asymptotic field fall-offs and thus their interpretation has remained incomplete. We improve on this situation by presenting a relaxation of the standard asymptotic field behavior that is compatible with O(r) gauge symmetries at linearized level. We show the extended space admits a symplectic structure on which O(1) and O(r) charges are well defined and such that their Poisson brackets reproduce the corresponding symmetry algebra.

“…(C.10) Such kind of terms are thus sensitive to (tree-level) double-soft gluon emission. See [73][74][75] for related discussion of double-soft emission and asymptotic charges.…”

Section: Jhep12(2021)058mentioning

confidence: 99%

Charge algebra for non-abelian large gauge symmetries at O(r)

Campiglia

Peraza

2021

“…For a generic theory of quantum gravity multiple soft graviton theorem was derived in [82] when all the gravitons are soft in the same rate(simultaneous limit). In [83,84] the double soft graviton theorem was analysed from asymptotic symmetry point of view and symmetry interpretation was found for consecutive limit i.e. when one of the soft graviton is softer than the other one.…”

Section: Introduction and Resultsmentioning

confidence: 99%

Subleading soft theorem for arbitrary number of external soft photons and gravitons

Bhatkar

Sahoo

2019

We obtain the subleading soft theorem for a generic theory of quantum gravity, for arbitrary number of soft photons and gravitons and for arbitrary number of finite energy particles with arbitrary mass and spin when all the soft particles are soft in the same rate. This result is valid at tree level for spacetime dimensions equal to four and five and to all loop orders in spacetime dimensions greater than five. We verify that in classical limit, low energy photon and graviton radiation decouple from each other.

Revisiting the shadow stress tensor in celestial CFT

Banerjee

Pasterski

2023

We revisit the standard construction of the celestial stress tensor as a shadow of the subleading conformally soft graviton. In its original formulation there is an obstruction to reproducing the expected $$ \overline{TT} $$ TT ¯ OPE in the double soft limit. We propose a modification to the definition which circumvents this obstruction and then extend this change of basis beyond the conformally soft and single helicity sectors. In the process we investigate how (non)-commutativity of double soft limits is tied to the decoupling of primary descendants, and how our choice of celestial basis determines which symmetries are manifest at the level of the OPE beyond the MHV sector.