Document Type
Course
Journal/Book Title/Conference
Physics 3710 – Intermediate Modern Physics, Spring 2018
Publication Date
1-8-2018
First Page
1
Last Page
4
Abstract
Antiscreening: The triumph of lattice QCD
QED is a phenomenally accurate theory of the interactions of electrically charged particles with photons. The way interactions are described in QED—by adding electromagnetic potential fields to the energy and momentum operators in the charged particle field equations— is essentially exactly correct given that the detailed calculations that can be made in QED agree so well with observation. These calculations are possible because simple processes (involving small numbers of interaction vertices) are significantly more important than complicated processes. That is, QED is a “perturbative” theory. Higher order QED effects, therefore, invariably consist of small corrections. QCD is different. The strength of the color interaction is greater than that of the electromagnetic interaction and, because gluons carry color, the processes that contribute importantly are more complex. In general, QCD is not a perturbative theory. Higher order QCD interactions are essential. While QED calculations typically involve only a few Feynman diagrams, QCD calculations of similar accuracy might involve hundreds of thousands!
Recommended Citation
Peak, David, "Structure of matter, 4" (2018). Structure of Matter. Paper 4.
https://digitalcommons.usu.edu/intermediate_modernphysics_matter/4