In quantum field theory, the 't Hooft loop is a magnetic analogue of the Wilson loop for which spatial loops give rise to thin loops of magnetic flux associated with magnetic vortices. They play the role of a disorder parameter for the Higgs phase in pure gauge theory. Consistency conditions between electric and magnetic charges limit the possible 't Hooft loops that can be used, similarly to the way that the Dirac quantization condition limits the set of allowed magnetic monopoles. They were first introduced by Gerard 't Hooft in 1978 in the context of possible phases that gauge theories admit.[1]
- ^ 't Hooft, G. (1978). "On the phase transition towards permanent quark confinement". Nuclear Physics B. 138 (1): 1–25. Bibcode:1978NuPhB.138....1T. doi:10.1016/0550-3213(78)90153-0.