Proper-Time Quantum Dynamics, Partitioned Hilbert Architecture, and Gate-Complete Chronology Violation in UV-Regulated Semiclassical Models

This paper formulates a gate-complete feasibility framework for testing whether literal backward arrival - defined operationally as arrival-before-departure relative to an exterior observer - can occur within a regulated semiclassical gravity model. The work addresses two established obstructions to chronology violation in semiclassical gravity: Divergences and algebraic pathologies at chronology horizons (including the Kay–Radzikowski–Wald obstruction). Quantum inequality constraints on negative energy required for compact chronology-violating geometries. The approach is structured as five binary gates (G0–G4), each equipped with a minimal decider and explicit falsifier: G0–G1: Laboratory-accessible proper-time quantum dynamics and record integrity under cyclic evolution via a Partitioned Hilbert Architecture (PHA). G2: Ultraviolet regularity at chronology horizons in an explicit action-level regulated theory. G3: A regulator-consistent quantum inequality bound translated into a finite-thickness support-layer design constraint. G4: A constrained feasibility search for self-consistent semiclassical solutions incorporating backreaction and thin-shell stability. The paper does not claim that chronology protection is evaded within standard semiclassical quantum field theory. Rather, it reduces the question of chronology violation to a finite set of model-specific theorems, numerical evaluations, and experimental deciders whose outcomes determine feasibility within the chosen regulated framework. The central contribution is architectural: converting the time-travel question from speculative narrative into a falsifiable decision structure grounded in semiclassical dynamics and operational verification.