Aharonov-Bohm effect as the basis of electromagnetic energy inherent in the vacuum

The Aharonov-Bohm effect shows that the vacuum is structured, and that there can exist a finite vector potential A in the vacuum when the electric field strength E and magnetic flux density B are zero. It is shown on this basis that gauge theory produces energy inherent in the vacuum. The latter is considered as the internal space of the gauge theory, containing a field made up of components of A, to which a local gauge transformation is applied to produce the electromagnetic field tensor, a vacuum charge/current density, and a topological charge g. Local gauge transformation is the result of special relativity and introduces spacetime curvature, which gives rise to an electromagnetic field whose source is a vacuum charge current density made up of A and g. The field carries energy to a device which can in principle extract energy from the vacuum. The development is given for U(1) and O(3) invariant gauge theory applied to electro dynamics.