Physical processes behind the emergence of fringes in superposition effects

We review the classical definition of the Mathematical Superposition Principle and the Measurable Superposition Effect, relevant to Young’s double-slit (YDS) experiment and the two-beam Mach–Zehnder Interferometer (MZI) and contrasts them with the prevailing interpretations by Quantum Mechanics. YDS is known to be “at the heart of understanding Quantum Mechanics” and MZI is being used to demonstrate quantum entanglement, a step forward to build quantum computers. We would demonstrate that classical interpretations are the correct ones for these two superposition effects. We recognize that cosmic universe is entangled by gravity and electromagnetic fields generated by innumerable stars of all the galaxies. Yet, we have succeeded in developing approximate mathematical theories, which we validate reproducibly by constructing local instruments for local and causal validity. Data in our instruments is generated as some physical transformation in a chosen “known entity” (detector) that exchanges energy with the “unknown entity” (detectee) under study. The energy exchange must always be guided by one of the natural forces of interaction, compatible between the detector and the detectee. This is known as the locality principle. Thus, all data-generating interactions represent locally entangled (interacting) phenomena. This is true irrespective of the expansive quantum-mathematical definition of the word “entanglement”. All useful engineering data is generated in an instrument as some physical transformation in a detector after it interacts and exchanges energy with one or more superposed signals stimulating it. The proper superposition equation, modeling such interaction processes, must incorporate the characteristic interaction parameter of the detector that would multiply all the superposed signals. Then the mathematically allowed normalization procedure of the unmeasurable summed amplitudes becomes constrained against ad hoc normalization. We recommend: (i) We need to underscore the explicit incorporation of the old fashion “Interaction Process Mapping Thinking” and bring back the engineering reality in all of Physics discourse. (ii) Experimental optical physicists should take active roles in the development of fundamental physics.