Abstract
Single-photon interference and delayed-choice experiments resist any account that treats the photon as a localized object carrying a private classical history. We propose the boundary-defined null connection (BDNC) view: a photon event is a null spacetime relation completed jointly by emission and absorption, with observable behavior fixed by the complete experimental boundary. The null-relation primitive itself is not novel — it appears in Kastner’s relativistic transactional interpretation, Sorkin’s causal-set null-link program, and the all-at-once / TSVF / Fixed Point Formulation literature.
The contribution is unifying language: BDNC compresses these into a single vocabulary and identifies one operational criterion — whether the boundary modifies only post-selected correlations or also unsorted marginals. The latter case, parameterized by a generic future-state weighting ansatz, amounts to no-signaling violation rather than a BDNC-specific law; we outline two marginal-stability protocols and one weak-measurement consistency check that would constrain such deviations. The principal claim is therefore a unifying diagnostic, not a new falsifiable prediction: any predictive version must derive a BDNC-specific functional form for the future-state weighting.
§ 11 sketches Twistor-Boundary Phase Geometry as a possible mathematical language for the framework, with the explicit caveat that minimal TBPG is empirically equivalent to standard twistor / gauge / QED.