On Wave Function Collapse at Radiative Boundaries

The physical mechanism responsible for wave function collapse remains an open question in the foundations of quantum theory. Existing objective reduction models usually rely on gravitational self-energy in the bulk, which makes it difficult to account for the rapid reduction of very light particles and does not naturally address massless quanta such as photons. In this work, a kinematic and mass-independent mechanism for wave function collapse is considered in which radiative emission across a geometric boundary is taken as the operational event associated with reduction. When a single quantum transition is evaluated at a radiative decoupling surface, the governing relation becomes boundary-normalized. Under this formulation both Boltzmann’s constant and Planck’s constant cancel algebraically, and the resulting rate is determined purely by boundary kinematics, Γ ∝ R²ω³ / c². The same structural scaling appears in the standard spontaneous-emission rate derived in quantum electrodynamics, while the fine-structure constant enters only as a dimensionless efficiency factor. Within this framework, quantum states may evolve unitarily in the bulk, whereas any radiative extraction of information into the classical domain must cross a finite decoupling surface. Collapse is therefore interpreted as an objective reduction associated with the finite transmission capacity of a radiative boundary. The Heisenberg cut is consequently assigned a concrete physical location at that boundary.