Interference Patterns Too Perfect for Local Propagation: Empirical Constraints on Modeling Beyond Transit Dynamics

This work analyzes single-quantum interference experiments from a strictly empirical perspective, focusing on the observable structure of detection patterns rather than on interpretational assumptions. Across more than a century of increasingly refined experiments, interference patterns exhibit a distinctive and robust combination of features: detection events are discrete and intrinsically unpredictable, yet their accumulated distribution converges rapidly to a stable, sharply structured pattern determined solely by the global experimental configuration. We show that these empirical properties impose strong constraints on admissible physical models. In particular, the sharpness, stability, and configuration-locked nature of interference minima are incompatible with explanations based on strictly local propagational mechanisms acting in transit between emission and detection. Local dynamical processes generically entail empirical signatures—such as intermediate observables, history dependence, noise-induced degradation of minima, or gradual pattern formation—that are systematically absent in interference data. By contrasting single-quantum interference experiments with genuine propagation measurements, where intermediate fields or particle properties are in principle accessible, we demonstrate that interference belongs to a different empirical category. What is observed is not the trace of a process evolving through space, but the spatial organization of discrete realization events at an absorbing boundary, governed by global structural constraints. The analysis does not introduce new experimental predictions at the level of local quantum measurements. Instead, it establishes that the empirical character of interference patterns itself necessitates a global, non-propagational modeling framework. Interference is therefore not merely compatible with such descriptions, but empirically excludes strictly local dynamical accounts. This work provides the empirical pillar of a broader global realization program, complementing prior conceptual and modeling studies.