Dress code for infrared safe scattering in QED

Abstract

We study the $S$-matrix and inclusive cross-section for general dressed states in quantum electrodynamics. We obtain an infrared factorization formula of the $S$-matrix elements for general dressed states. It enables us to study what dressed states lead to infrared-safe $S$-matrix elements. The condition for dressed states can be interpreted as the memory effect which is nothing but the conservation law of the asymptotic symmetry. We derive the generalized soft photon theorem for general dressed states. We also compute inclusive cross-section using general dressed states. It is necessary to use appropriate initial and final dressed states to evaluate interference effects, which cannot be computed correctly by using Fock states due to the infrared divergence.

47 pages + appendices, no figure; v2: minor edit, references added; v3: clarifications added in subsection 5.1, new appendix D added and typos corrected

References in corpus (10)

• Low's Subleading Soft Theorem as a Symmetry of QED
• Shaving off Black Hole Soft Hair
• Celestial Amplitudes from UV to IR
• Large Gauge Symmetries and Asymptotic States in QED
• Infrared quantum information
• Dressed infrared quantum information
• Dressed states from gauge invariance
• Target space entanglement in quantum mechanics of fermions and matrices
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Cited by in corpus (3)

• New Laboratory Constraints on Neutrinophilic Mediators
• Coherent States in Gauge Theories: Topological Defects and Other Classical Configurations
• Subleading soft radiation during scattering of dressed states in QED