Subleading soft radiation during scattering of dressed states in QED

Abstract

We study soft photon emission during scattering of Faddeev-Kulish charged states in QED, at leading order in perturbation theory. The charged asymptotic particles are accompanied by clouds of an infinite number of soft photons of energy less than a characteristic infrared scale $E_d$. When the corresponding ``dressing'' functions are suitably corrected to subleading order in the soft momentum expansion, as advocated in recent work by Choi and Akhoury, we show explicitly that the emission of additional radiative soft photons with energy less than $E_d$ is completely suppressed. Moreover, the dressing renders the elastic amplitudes infrared-finite, order by order in perturbation theory, regulating the infrared divergences due to virtual soft photons, at the energy scale $E_d$. Therefore, the characteristic energy scale of the soft photons in the clouds provides an effective infrared cutoff, allowing for the formulation of an infrared finite S-matrix.

arXiv commentRevised version following peer review

References in corpus (36)

• Soft Hair on Black Holes
• On BMS Invariance of Gravitational Scattering
• BMS supertranslations and Weinberg's soft graviton theorem
• New Symmetries of Massless QED
• Low's Subleading Soft Theorem as a Symmetry of QED
• Low-Energy Behavior of Gluons and Gravitons from Gauge Invariance
• On Loop Corrections to Subleading Soft Behavior of Gluons and Gravitons
• Loop Corrections to Soft Theorems in Gauge Theories and Gravity
• Infrared Divergences in QED, Revisited
• Classical and Quantum Results on Logarithmic Terms in the Soft Theorem in Four Dimensions
• Shaving off Black Hole Soft Hair
• More on Soft Theorems: Trees, Loops and Strings
• Logarithmic Terms in the Soft Expansion in Four Dimensions
• The SAGEX Review on Scattering Amplitudes
• Large Gauge Symmetries and Asymptotic States in QED
• Infrared quantum information
• BMS Supertranslation Symmetry Implies Faddeev-Kulish Amplitudes
• Classical Sub-subleading Soft Photon and Soft Graviton Theorems in Four Spacetime Dimensions
• Loop Corrected Soft Photon Theorem as a Ward Identity
• On the need for soft dressing
• Note on soft theorems and memories in even dimensions
• Dressed infrared quantum information
• On the Subleading-Soft Behaviour of QCD Amplitudes
• Subleading soft dressings of asymptotic states in QED and perturbative quantum gravity
• Scattering and momentum space entanglement
• Dressed states from gauge invariance
• Testing Subleading Multiple Soft Graviton Theorem for CHY Prescription
• Infrared Divergences and Quantum Coherence
• IR dynamics and entanglement entropy
• IR finite S-matrix by gauge invariant dressed states
• The Scales of the Infrared
• Gravitational soft theorem from emergent soft gauge symmetries
• Magnetic Soft Charges, Dual Supertranslations and 't Hooft Line Dressings
• Dress code for infrared safe scattering in QED
• Soft photon radiation and entanglement
• Soft Theorems from Boundary Terms in the Classical Point Particle Currents