This is a general and powerful method which results in Eq. (8), valid for any scalar function. It applies to scalar and vector potentials and fields such as E, B, and g. Eq. (27) defines the vacuum driving force for the vacuum electric field. This can be amplified by Euler Bernoulli resonance. The Euler Bernoulli equation defines the circuit design needed to greatly amplify a vacuum fluctuation of type (27). This is very important for practical applications. There have been several experimental demonstrations of such resonance effects in a circuit, notably the demonstration by the Alex Hill group to the US Navy in 2005. Since then thee has been tremendous theoretical and experimental progress.