scholarly journals Ward identity for loop level soft photon theorem for massless QED coupled to gravity

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Sayali Atul Bhatkar
Keyword(s):  
Long Range ◽  
Conservation Law ◽  
Ward Identity ◽  
Gravitational Force ◽  
Soft Photon ◽  
Loop Level ◽  
New Feature ◽  
Loop Amplitudes

Abstract Motivated by Campiglia and Laddha [1], we show that the Sahoo-Sen soft photon theorem [2] for loop amplitudes is equivalent to an asymptotic conservation law. This asymptotic charge is directly related to the dressing of fields due to long range forces exclusively present in four spacetime dimensions. In presence of gravity, the new feature is that photons also acquire a dressing due to long range gravitational force and this dressing contributes to the asymptotic charge.

scholarly journals Classical sub-subleading soft photon and soft graviton theorems in four spacetime dimensions

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Biswajit Sahoo
Keyword(s):  
Fourier Transformation ◽  
Soft Photon ◽  
Scattering Process ◽  
Retarded Time ◽  
Long Wavelength ◽  
Macroscopic Objects ◽  
Loop Amplitudes

Abstract 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 outgoing macroscopic objects. Performing Fourier transformation of the electromagnetic and gravitational waveforms in the frequency variable one finds electromagnetic and gravitational waveforms at late and early retarded time. Here extending the formalism developed in [1], we derive sub-subleading electromagnetic and gravitational waveforms which behave like u−2(ln u) at early and late retarded time u in four spacetime dimensions. We also have derived the sub-subleading soft photon theorem analyzing two loop amplitudes in scalar QED. Finally, we conjectured the structure of leading non-analytic contribution to (sub)n-leading classical soft photon and graviton theorems which behave like u−n(ln u)n−1 for early and late retarded time u.

scholarly journals Infinite-dimensional fermionic symmetry in supersymmetric gauge theories

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Thomas T. Dumitrescu ◽  
Temple He ◽  
Prahar Mitra ◽  
Andrew Strominger
Keyword(s):  
Ward Identity ◽  
Gauge Theories ◽  
Soft Photon ◽  
Supersymmetric Gauge Theories ◽  
Null Infinity ◽  
Infinite Dimensional ◽  
Charged Matter ◽  
Gauge Symmetries ◽  
Supersymmetric Gauge

Abstract We establish the existence of an infinite-dimensional fermionic symmetry in four-dimensional supersymmetric gauge theories by analyzing semiclassical photino dynamics in abelian $$ \mathcal{N} $$ N = 1 theories with charged matter. The symmetry is parametrized by a spinor-valued function on an asymptotic S2 at null infinity. It is not manifest at the level of the Lagrangian, but acts non-trivially on physical states, and its Ward identity is the soft photino theorem. The infinite-dimensional fermionic symmetry resides in the same $$ \mathcal{N} $$ N = 1 supermultiplet as the physically non-trivial large gauge symmetries associated with the soft photon theorem.

scholarly journals Loop corrected soft photon theorem as a Ward identity

2019 ◽  
Vol 2019 (10) ◽  
Author(s):  
Miguel Campiglia ◽  
Alok Laddha
Keyword(s):  
Ward Identity ◽  
Soft Photon

scholarly journals Towards LHC phenomenology at the loop level: A new method for one-loop amplitudes

2006 ◽  
Vol 157 (1) ◽  
pp. 48-52 ◽  
Author(s):  
T. Binoth ◽  
M. Ciccolini ◽  
G. Heinrich
Keyword(s):  
New Method ◽  
Loop Level ◽  
Loop Amplitudes

New Feature of Long-Range Correlations in Hadron-nucleus Interactions

1993 ◽  
Vol 10 (12) ◽  
pp. 712-715
Author(s):  
Shengqin Feng ◽  
Daicui Zhou
Keyword(s):  
Long Range ◽  
Long Range Correlations ◽  
New Feature

scholarly journals Studies of structure formation in theories with a repulsive long-range gravitational force

1997 ◽  
Vol 14 (3) ◽  
pp. 199-207 ◽  
Author(s):  
D. Lohiya ◽  
A. Batra ◽  
S. Mehra ◽  
S. Mahajan ◽  
A. Mukherjee
Keyword(s):  
Structure Formation ◽  
Long Range ◽  
Gravitational Force

scholarly journals New asymptotic conservation laws for electromagnetism

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Sayali Atul Bhatkar
Keyword(s):  
Electromagnetic Field ◽  
Conservation Laws ◽  
Infinite Number ◽  
Conservation Law ◽  
Classical Limit ◽  
Soft Photon ◽  
Memory Term ◽  
Late Time

Abstract We obtain the subleading tail to the memory term in the late time electromagnetic radiative field generated due to a generic scattering of charged bodies. We show that there exists a new asymptotic conservation law which is related to the subleading tail term. The corresponding charge is made of a mode of the asymptotic electromagnetic field that appears at $$ \mathcal{O} $$ O (e5) and we expect that it is uncorrected at higher orders. This hints that the subleading tail arises from classical limit of a 2-loop soft photon theorem. Building on the m = 1 [41, 42] and m = 2 cases, we propose that there exists a conservation law for every m such that the respective charge involves an $$ \mathcal{O} $$ O (e2m+1) mode and is conserved exactly. This would imply a hierarchy of an infinite number of m-loop soft theorems. We also predict the structure of mth order tails to the memory term that are tied to the classical limit of these soft theorems.

scholarly journals Lanczos potential of Weyl field: interpretations and applications

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Ram Gopal Vishwakarma
Keyword(s):  
Building Block ◽  
Physical Meaning ◽  
Potential Field ◽  
Tensor Field ◽  
Gravitational Force ◽  
Lanczos Potential ◽  
Fundamental Building Block ◽  
Domain Of Applicability ◽  
Relativistic Analogue ◽  
New Feature

AbstractAn attempt is made to uncover the physical meaning and significance of the obscure Lanczos tensor field which is regarded as a potential of the Weyl field. Despite being a fundamental building block of any metric theory of gravity, the Lanczos tensor has not been paid proper attention as it deserves. By providing an elucidation on this tensor field through its derivation in some particularly chosen spacetimes, we try to find its adequate interpretation. Though the Lanczos field is traditionally introduced as a gravitational analogue of the electromagnetic 4-potential field, the performed study unearths its another feature – a relativistic analogue of the Newtonian gravitational force field. A new domain of applicability of the Lanczos tensor is introduced which corroborates this new feature of the tensor.

Infrared Effects

2021 ◽  
pp. 334-348
Author(s):  
J. Iliopoulos ◽  
T.N. Tomaras
Keyword(s):  
Long Range ◽  
Perturbation Expansion ◽  
Coulomb Scattering ◽  
Physical Origin ◽  
Zero Mass ◽  
Loop Level ◽  
S Matrix ◽  
Infrared Divergences ◽  
Double Logarithm

It is shown that the presence of zero mass particles makes the elements of the S-matrix divergent. We explain the physical origin of such divergences. We argue that they are due to the long range of the interactions which violate the assumptions we made when we derived the asymptotic conditions for scattering. We study these divergences in the particular case of QED at tree, as well as one-loop level and present the Bloch–Nordsieck solution. We show that the cancellation of infrared divergences among virtual exchanged and real emitted soft photons is true to all orders in the perturbation expansion and we obtain the Sudakov double logarithm formula for Coulomb scattering.

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