The Neutron Scale Constraint in MPCT-He Model: A Minimalist Approach to Atomic Scale Determination

We introduce a minimal neutron scale constraint term within the MPCT-He (Multielectron Phase Closure Theory for Helium) framework. Remarkably, this single addition—while leaving all other physical definitions and calculation logics unchanged—successfully corrects the predicted helium radius from 9.5 Å to 0.28 Å, achieving a 9.7% error relative to the experimental value of 0.31 Å. Simultaneously, the electron configuration self-corrects from the erroneous to the correct , and the closure stability increases from 0.6 to 0.9. This demonstrates that neutron constraints function not merely as nuclear descriptors but as fundamental existential constraints governing material scale.Keywords: Neutron constraint, atomic scale, MPCT-He model, existential physics, minimal modification