Paper7_Wave-like Propagation, Decoherence, and Effective Localization from the Visible Action in the B Framework

We study whether wave-particle duality can be approached from the visible action of the α-β-φ framework. We begin from the linearized visible sector, where φ acts as the visible propagating channel and β as the structural channel, with both sectors mixed by the action-derived Hessianμφβ = ∂φ∂βV |0. We then couple the visible system to an external environment through anobservable combination O = δβ + η δφ. After integrating out the environment, we derive areduced master equation whose decoherence term suppresses off-diagonal coherences in the Obasis. Finally, for a two-packet Gaussian superposition, we obtain an explicit detection profile inwhich the interference term is exponentially damped by the decoherence rate Γ = D0(OL−OR)2.The result provides a controlled action-based route from coherent wave-like propagation toeffective particle-like localization in the linearized visible sector. The derivation is effective,open-system, and branch-level; it does not yet amount to a complete nonperturbative theory ofmeasurement in the full interacting framework.