Dynamical Couplings in gauge theories and relation to Confinement Mechanisms

By using a variation of the gauge procedure which employs a scalar gauge field B x in addition to the usual vector gauge field A mu x we can couple abelian gauge fields to currents which allow dynamical coupling constants which could depend for example on the local value of a scalar field In the most simple realization of these models such theories naturally lead to a confinement of charge inside bags where the charge current is confined inside Bags via MIT Bag model boundary conditions Other formulations allow the possibility of gauge invariant formulation of dynamical couplings like for example time dependent fine structure constant without associated confinement mechanisms