Soo-Jong Rey

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I recast the cancellation of infrared(IR) divergences in QED
using the Schwinger-Keldysh closed time path formalism and the framework of
open quantum systems. Treating soft radiation photons as the environment, I
show that IR cancellation is trace preservation of the resulting quantum
channel — unitarity of the open system inherited from the full theory. The
Sudakov form factor is the exclusive Kraus operator norm, and the
Nakajima-Zwanzig master equation with an Ohmic memory kernel provides a
dynamical reformulation of the Sudakov resummation. We extend the framework
to QED in 1+1 dimensions, where the absence of propagating photons and the
chiral anomaly produce a novel non-Markovian universality class at
radiation threshold. I connect this naturally to Fermi edge singularities
in condensed matter, where similar structure appears.

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Kwangwoon University, Korea
0.03
Contact: Sebastian Diehl