The role of

gauge invariance in physics is analogous to an equivalence class in mathematics.

I think that the treatment of the scalar multiplet actions in the present work may contain clues to supergravity, both considering the extra

gauge invariances and the extra factors of [lambda] in the action.

Baranov, (Mis-)handling

Gauge Invariance in the Theory of the Quantum Hall Effect.

Introduces the

gauge invariance property of acoustic equation of motion, with applications in the elastic constants of isotropic solids, time reversal acoustics, negative refraction, double negative acoustical metamaterial and acoustical cloaking.

Within this essential reference logical organization of the material on

gauge invariance, quantization, and renormalization is also discussed providing necessary reading for Cosmologists and Particle Astrophysicists.

Also, the lagrangian can still be completely massless (as in the Higgs scenario), preserving attractive features such as

gauge invariance that would be broken by explicit mass terms, the generation of mass being a secondary physical phenomenon.

For example, in the Standard Model, due to its chiral nature, a Higgs field is introduced in order to manifest

gauge invariance.

The SL(2,C) gauge invariance of Weyl is the most well-known, although others may prefer SL(6,C), for instance Abdus Salam et al.

Perhaps it is not quite an exaggeration to remark here that most subsequent developments in both elementary particle physics and also hadron physics were advanced by YangMills' effort to generalize the gauge invariance [8].

This term term couldn't be added to the initial Lagrangian because, it breaks the ordinary

gauge invariance.

A modified form of local

gauge invariance in which fermion field phase is allowed to vary with each space point but not each time point, leads to the introduction of a new compensatory field different from the electromagnetic field associated with the photon.

One purpose is to find a gauge fixing condition for eliminating the degenerate degree of freedom from the

gauge invariance of the above quantum gauge theory in Section 2.