Local (Gauge) Invariance
In the preceding chapter we have considered the groups of global transformations and the Lagrangian invariant under these groups. A globally invariant Lagrangian can, however, be non-invariant under a certain group of local transformations. To obtain a locally invariant Lagrangian, new fields have to be introduced. These are called gauge fields.
KeywordsGauge Group Covariant Derivative Gauge Field Local Group Lorentz Group
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