Detector-Plane Causality in Quantum Measurement

Detector-Plane Causality in Quantum Measurement: A Benchmark Framework for Measurement Integrity and Control This work introduces an instrumentation-level framework for analyzing quantum measurement systems by explicitly localizing irreversible information loss at the detector plane. The detector plane is defined as the combined system consisting of detector materials, front-end electronics, digitization hardware, firmware, and software reconstruction that transform physical detection events into recorded measurement data. The paper proposes the Quantum Measurement Stack (QMS), a causally ordered abstraction that decomposes quantum experiments into operational layers: Field excitation and imprint formation Detector-plane imaging Data acquisition (DAQ) integrity Quantum diagnostics Quantum control system (QCS) Within this framework, the detector plane acts as the effective measurement boundary where correlations can be irreversibly preserved or discarded. To operationalize this concept, the work introduces QMCTB-01, a detector-plane causality benchmark based on a near-field double-slit configuration. The benchmark evaluates two detector regimes under identical photon statistics and propagation conditions: Intensity-only detection, where phase correlations are discarded at the detector plane. Correlation-preserving detection, where phase information is retained through the detector pipeline. Wave-optics simulations demonstrate that interference visibility is determined by detector-plane coherence preservation, not by statistical accumulation of detection events. When correlations are discarded at the detector plane, interference fringes cannot be recovered through averaging, filtering, or post-processing, consistent with established limits of digital signal processing and information theory. The results establish detector-plane coherence fidelity as a measurable instrumentation property and provide a practical benchmark for evaluating detector systems across quantum optics, solid-state detectors, and hybrid quantum platforms. This work frames quantum interference experiments as an instrumentation and signal-processing problem, providing a reproducible methodology for diagnosing detector-induced coherence loss and for designing measurement pipelines that preserve physically relevant correlations. Simulation code and benchmark artifacts supporting this work are available through the associated repository.