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Related papers: Loop Corrected Soft Photon Theorem as a Ward Ident…

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Large Gauge Transformations (LGT) are gauge transformations that do not vanish at infinity. Instead, they asymptotically approach arbitrary functions on the conformal sphere at infinity. Recently, it was argued that the LGT should be…

High Energy Physics - Theory · Physics 2017-02-01 Barak Gabai , Amit Sever

We consider the scattering of massless particles coupled to an abelian gauge field in 2n-dimensional Minkowski spacetime. Weinberg's soft photon theorem is recast as Ward identities for infinitely many new nontrivial symmetries of the…

High Energy Physics - Theory · Physics 2014-12-10 Daniel Kapec , Vyacheslav Lysov , Andrew Strominger

Soft factorization theorems can be reinterpreted as Ward identities for (asymptotic) symmetries of scattering amplitudes in asymptotically flat space-time. In this paper we study the symmetries implied by the all loop soft photon theorems…

High Energy Physics - Theory · Physics 2026-03-11 Shamik Banerjee , Raju Mandal , Biswajit Sahoo

Classical soft photon and soft graviton theorems determine long wavelength electromagnetic and gravitational waveforms for a general classical scattering process in terms of the electric charges and asymptotic momenta of the ingoing and…

High Energy Physics - Theory · Physics 2020-12-30 Biswajit Sahoo

The logarithmic soft photon theorem in four spacetime dimensions encodes an infinite-dimensional asymptotic symmetry which acts on massive matter as a divergent superphaserotation. Here we extend this result to massless matter which is both…

High Energy Physics - Theory · Physics 2026-01-12 Sangmin Choi , Ameya Kadhe , Andrea Puhm

The symmetries of asymptotically flat spacetimes impose constraints on observables at infinity. The consequences of this have been extensively explored for S-matrix elements, where soft theorems are known to be equivalent to Ward identities…

High Energy Physics - Theory · Physics 2025-12-03 Ian Moult , Sruthi A. Narayanan , Sabrina Pasterski

The soft photon theorem in U(1) gauge theories with only massless charged particles has recently been shown to be the Ward identity of an infinite-dimensional asymptotic symmetry group. This symmetry group is comprised of gauge…

High Energy Physics - Theory · Physics 2015-06-10 Daniel Kapec , Monica Pate , Andrew Strominger

Recently, the leading soft gluon theorem with single soft emission was shown to be the Ward identity of a two dimensional $\cal G$-Kac-Moody symmetry. In this note, we show that the leading soft gluon theorem can be interpreted as the Ward…

High Energy Physics - Theory · Physics 2021-10-12 Pujian Mao , Jun-Bao Wu

Various equivalences between so-called soft theorems which constrain scattering amplitudes and Ward identities related to asymptotic symmetries have recently been established in gauge theories and gravity. So far these equivalences have…

High Energy Physics - Theory · Physics 2015-05-21 Miguel Campiglia , Alok Laddha

It is known that soft photon and graviton theorems can be regarded as the Ward-Takahashi identities of asymptotic symmetries. In this paper, we consider soft theorem for pions, i.e., Nambu-Goldstone bosons associated with a spontaneously…

High Energy Physics - Theory · Physics 2018-01-17 Yuta Hamada , Sotaro Sugishita

In this paper, we revisit the question of identifying Soft Graviton theorem in higher (even) dimensions with Ward identities associated with Asymptotic symmetries. Building on the prior work of \cite{strominger}, we compute, from first…

High Energy Physics - Theory · Physics 2019-02-04 Ankit Aggarwal

S-matrix elements exhibit universal factorization when multiple infrared photons are emitted in scattering processes. We explicitly show that the leading soft factorization of tree-level amplitudes with the emission of any number of soft…

High Energy Physics - Theory · Physics 2021-10-13 Zhengwen Liu , Pujian Mao

We show that the subleading soft photon theorem in a $(d+2)$-dimensional massless abelian gauge theory gives rise to a Ward identity corresponding to divergent large gauge transformations acting on the celestial sphere at null infinity. We…

High Energy Physics - Theory · Physics 2020-01-08 Temple He , Prahar Mitra

We extend a previously developed formulation of the S-matrix, based on a path integral with asymptotic boundary conditions, to include gravity. The path integral defines a Carrollian boundary partition function whose invariance under…

High Energy Physics - Theory · Physics 2026-05-12 Jack Isen , Per Kraus , Ruben Monten , Richard M. Myers

We consider soft electrons in massless QED at tree-level. The emission amplitude at leading order in the soft electron energy factorizes in a way similar to the soft photon case. We recast the soft electron factorization formula as a Ward…

High Energy Physics - Theory · Physics 2023-07-24 Adrián Agriela , Miguel Campiglia

We present a Ward identity for nonlinear sigma models using generalized nonlinear shift symmetries, without introducing current algebra or coset space. The Ward identity constrains correlation functions of the sigma model such that the…

High Energy Physics - Theory · Physics 2018-02-26 Ian Low , Zhewei Yin

Classical soft theorems applied to probe scattering processes on AdS$_4$ spacetimes predict the existence of $1/L^2$ corrections to the soft photon and soft graviton factors of asymptotically flat spacetimes. In this paper, we establish…

High Energy Physics - Theory · Physics 2023-05-03 Nabamita Banerjee , Karan Fernandes , Arpita Mitra

The universality of the logarithmic soft photon theorem in four dimensions can be traced to an infinite-dimensional asymptotic symmetry which acts as a local phase rotation on matter as we have shown in 2403.13053. Here we extend our…

High Energy Physics - Theory · Physics 2025-09-23 Sangmin Choi , Alok Laddha , Andrea Puhm

We identify in Einstein gravity an asymptotic spin-$2$ charge aspect whose conservation equation gives rise, after quantization, to the sub-subleading soft theorem. Our treatment reveals that this spin-$2$ charge generates a non-local…

High Energy Physics - Theory · Physics 2022-06-15 Laurent Freidel , Daniele Pranzetti , Ana-Maria Raclariu

We present several results on memory effects, asymptotic symmetry and soft theorems in massive QED. We first clarify in what sense the memory effects are interpreted as the charge conservation of the large gauge transformations, and derive…

High Energy Physics - Theory · Physics 2018-08-15 Hayato Hirai , Sotaro Sugishita