Editing Quantum field theory (section)

===Condensed-matter-physics===
Although quantum field theory arose from the study of interactions between elementary particles, it has been successfully applied to other physical systems, particularly to [[many-body system]]s in [[condensed matter physics]].

Historically, the Higgs mechanism of spontaneous symmetry breaking was a result of [[Yoichiro Nambu]]'s application of [[superconductor]] theory to elementary particles, while the concept of renormalization came out of the study of second-order [[phase transition]]s in matter.<ref>{{cite web |url=https://science.energy.gov/~/media/hep/pdf/Reports/HEP-BES_Roundtable_Report.pdf |title=Common Problems in Condensed Matter and High Energy Physics |date=2015-02-02 |website=science.energy.gov |publisher=Office of Science, [[U.S. Department of Energy]] |access-date=2018-07-18}}</ref>

Soon after the introduction of photons, Einstein performed the quantization procedure on vibrations in a crystal, leading to the first [[quasiparticle]]—[[phonon]]s. Lev Landau claimed that low-energy excitations in many condensed matter systems could be described in terms of interactions between a set of quasiparticles. The Feynman diagram method of QFT was naturally well suited to the analysis of various phenomena in condensed matter systems.<ref name="wilczek">{{Cite journal |last=Wilczek |first=Frank |author-link=Frank Wilczek |arxiv=1604.05669 |title=Particle Physics and Condensed Matter: The Saga Continues |journal=Physica Scripta |volume=2016 |issue=T168 |pages=014003 |date=2016-04-19 |bibcode=2016PhST..168a4003W |doi=10.1088/0031-8949/T168/1/014003 |s2cid=118439678 }}</ref>

Gauge theory is used to describe the quantization of [[magnetic flux]] in superconductors, the [[resistivity]] in the [[quantum Hall effect]], as well as the relation between frequency and voltage in the AC [[Josephson effect]].<ref name="wilczek" />