The Gravitational Constraint of Vacuum Energy Boundary-Induced Stress and Spacetime Geometry

This paper analyzes the physical necessity linking vacuum energy modified by boundary conditions to spacetime curvature in General Relativity. Using only experimentally established facts — that boundary conditions produce finite vacuum energy differences (as in the Casimir effect) and that General Relativity universally couples stress-energy to geometry — it shows that any finite, physically real redistribution of vacuum energy must produce spacetime curvature. The argument avoids mathematical formalism and speculative mechanisms, instead focusing on the unavoidable logical consequence that physically instantiated vacuum stress cannot be gravitationally inert if gravity couples universally. This identifies a conceptual gap in how quantum vacuum configurations are often treated in the literature and closes it with a physics-only necessity argument.