The Vacuum as a Thin Four-Dimensional Gap: Inner-Outer Wall Dynamics as the Common Origin of Electromagnetism, Gravity, and Rotor Matter

This paper proposes that the physical vacuum can be modeled as a very thin, pressure-bearing four-dimensional gap between two limiting sides of the observable cosmic hypersurface, described here as an inner wall and an outer wall. Building on the pressure-driven cosmological framework developed in R190, the model treats local vacuum behavior as the small-scale expression of the same four-dimensional boundary structure that governs cosmic expansion. Signed wall separation is interpreted as the geometric basis of electric-type distortion, tangential wall shear as the basis of magnetic-type behavior, and common wall-pair curvature as the gravitational limit. With calibrated wall-gap and wall-shear variables, Maxwell's equations are recovered in their standard form, while general relativity is interpreted as the large-scale curvature limit of the wall-pair calibrated by Newton's gravitational constant. Matter is described as localized topological opening or rotor-supported organization of the gap, allowing charge, magnetic moment, mass, and neutron metastability to be interpreted as different wall-supported states. Recent four-dimensional particle simulations are discussed as exploratory constraints, especially their indication that a simple symmetric fourth-coordinate squeeze is insufficient and that signed inner-wall and outer-wall dynamics are required. The paper identifies the constants, calibrations, simulations, and open problems needed to develop the thin-gap model into a quantitative theory.