Ghost particles could obtain the symmetry or break it in gauge fields.

Without any additional constraints, the bridge wouldn't give all the information about the gauge field.

Now, the bridge gives exactly the same information content as the gauge field.

The part of the gauge field in this direction stays massless, and amounts to the physical photon.

So in the abelian Higgs model, the gauge field acquires a mass.

Consequently, it can be treated as a gauge field.

It can also be regarded as the gauge field generated by local Lorentz transformations.

The gauge field becomes an essential part of the description of a mathematical configuration.

The charges of the theory "radiate" the gauge field.

The next step is to "couple" the gauge fields to the fermions, allowing for interactions.