Event‑Level Closure of Gravity in Quantum Measurement: An Operational QMTF Proof in Semiclassical QM+GR

Operational theorem package: R′ (resolution), T′ (common-mode invariance), C′ (sub-bin curvature irrelevance), D′ (near-null registrar trivialization), H′ (horizon implementability) This record contains the final manuscript and supporting materials for a strictly operational analysis of quantum measurement in spacetime. Following the introduction of Quantum Measurement Timeline Framework (QMTF), in which a measurement is defined as a POVM statement on a declared spacetime target frameD* = R* × T* at finite resolution (Δx, Δt). An event is the realization of a single POVM effect E_U on one spacetime bin U; all dynamical relations among alternatives—including gravitational influence—belong to pre-event evolution. Within this orthodox setting, we prove a five-part operational theorem package: R′ (resolution). Finite operational resolution is derived, not assumed, from the metrological chain quantum Fisher information → Bures/Fidelity → total variation distance, yielding explicit Δx_min and Δt_min at any discrimination threshold ε_disc. T′ (common-mode invariance). Uniform time dilation or global phases are probability-irrelevant for any POVM; only differential phases can affect outcome statistics. C′ (sub-bin curvature irrelevance). Curvature variations confined below the declared resolution cannot change single-bin event probabilities beyond ε_disc. After Hadamard-controlled spatial and temporal smearing, such effects are common-mode or strictly sub-threshold. D′ (near-null registrar trivialization). With finite information rate, the boundTVD ≤ √(F / 8) · τ implies that no nontrivial discrimination is possible as the registrar’s proper-time budget τ → 0. H′ (horizon implementability). An exterior laboratory cannot implement POVM effects localized strictly in the interior algebra of a black-hole spacetime; interior bins have zero operational support for exterior observers. Together, these results close “gravity at the event” in the single-run semiclassical domain: gravity can only shape pre-event phases and support via proper time and cannot appear as an event-internal degree of freedom at any finite operational resolution. Each theorem is stated with explicit inequalities and clean falsifiers (sub-resolution curvature tests, near-null discrimination limits, and exterior-only interior implementability), ensuring refutability. The framework uses no assumptions beyond standard quantum mechanics (POVMs and instruments) and general relativity (proper time and locality) and is consistent with interferometric observations such as COW neutron interferometry and Kasevich–Chu atom interferometers, where gravity appears exclusively through differential pre-event phases. Keywords: POVM measurement; operational quantum measurement; quantum Fisher information; distinguishability bounds; Unruh–DeWitt detector; Hadamard states; proper time; semiclassical quantum mechanics and general relativity; algebraic quantum field theory; interferometry, QMTF. Author: R. Necsanu ORCID: 0009‑0009‑1281‑9180 Reference record (QMTF): Necsanu (2026), Zenodo 10.5281/zenodo.18262158