From QEC to Hilbert: A UBL → DHP Plateau Contract

After an extensive search this article is believed to be another first. It consolidates scattered laboratory heuristics into a single, falsifiable operating contract for quantum error correction. Unified Balance-Line (UBL) mapping is introduced to locate and certify R≈1 plateaus; a Directive Handoff Protocol (DHP) enforces no-backflow during the measure → buffer → decode → correct cycle; and a “two-green” admission rule requires both geometry and process to pass inside a tokened window. The result is a practical, hardware-agnostic discipline: map, issue a hold-token, run independence drills (swaps, flip-only Z, disable-L), and make claims only where evidence is strongest—never on the fringes and never with retroactive data reuse. Beyond projector-only Hilbert treatments, the framework adds explicit falsifiers, a reproducible mapping pipeline, ROC-style threshold tuning, a decoder/throughput budget, and an auditable ledger. A c-limited, QCore-first posture is also articulated: finish sooner with locality, shallow fragments, and fast feed-forward; attach a Hilbert-guarded qLDPC or bosonic “memory island” only when dwell time or entanglement radius demands it. The contract is portable across platforms and designed to be refuted if it fails—by construction. Included materials: a one-page bench-run card, mapping checklist, admit-vs-abort table, pseudocode for UBL and DHP loops, and a reproducibility kit (constants to preregister, run-bound uniques to freeze, and minimum logs to export).