Editing Faddeev–Popov ghost (section)

{{Short description|Type of unphysical field in quantum field theory which provides mathematical consistency}}
{{about|a specific type of ghost field|ghosts in the general physics sense|Ghosts (physics)}}
{{Quantum field theory|cTopic=Some models}}
{{more footnotes needed |date=February 2020}}

In [[physics]], '''Faddeev–Popov ghosts''' (also called '''Faddeev–Popov gauge ghosts''' or '''Faddeev–Popov ghost fields''') are extraneous [[field (physics)|fields]] which are introduced into [[gauge theories|gauge]] [[quantum field theory|quantum field theories]] to maintain the consistency of the [[path integral formulation]]. They are named after [[Ludvig Faddeev]] and [[Victor Popov]].<ref>{{Cite journal |last1=Faddeev |first1=L.D. |author-link=Ludvig Faddeev |last2=Popov |first2=V.N. |author-link2=Victor Popov |date=July 1967 |title=Feynman diagrams for the Yang-Mills field |journal=[[Physics Letters B]] |language=en |volume=25 |issue=1 |pages=29–30 |bibcode=1967PhLB...25...29F |doi=10.1016/0370-2693(67)90067-6}}</ref><ref>{{Cite journal |last=Chen |first=W. F. |date=April 2013 |title=Differential geometry from quantum field theory |journal=[[International Journal of Geometric Methods in Modern Physics]] |volume=10 |issue=4 |page=1350003 |arxiv=0803.1340 |doi=10.1142/S0219887813500035 |issn=0219-8878 |s2cid=16651244}}</ref>

A more general meaning of the word "ghost" in [[theoretical physics]] is discussed in [[Ghost (physics)]].