The Kinoshita–Lee–Nauenberg theorem or KLN theorem states that perturbatively the
standard model
The Standard Model of particle physics is the theory describing three of the four known fundamental forces (electromagnetism, electromagnetic, weak interaction, weak and strong interactions - excluding gravity) in the universe and classifying a ...
as a whole is infrared (IR) finite. That is, the
infrared divergences coming from loop integrals are canceled by IR divergences coming from
phase space
In dynamical system theory, a phase space is a space in which all possible states of a system are represented, with each possible state corresponding to one unique point in the phase space. For mechanical systems, the phase space usually ...
integrals. It was introduced independently by and .
An analogous result for
quantum electrodynamics alone is known as Bloch–Nordsieck theorem.
Ultraviolet divergences in perturbative
quantum field theory
In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines classical field theory, special relativity, and quantum mechanics. QFT is used in particle physics to construct physical models of subatomic particles and ...
are dealt with in
renormalization.
References
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*Taizo Muta, Foundations of Quantum Chromodynamics: An Introduction to Perturbative Methods in Gauge Theories, World Scientific Publishing Company; 3 edition (September 30, 2009)
Standard Model
Quantum field theory
Theorems in quantum mechanics
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