Periodic admission control (AC) can change when accepted events occur within a cycle even when long-run averages (e.g. total accepted injections per unit time) are unchanged. This "temporal bias" matters whenever logical-flip risk is phase-dependent or when analysts condition on accepted events without correcting for exposure. We formalize an exposure-proportional null for phase-resolved logical flips and propose two lightweight diagnostics: (i) a Poisson sinusoid regression on log-risk with an exposure offset, and (ii) an exact window-enrichment test (binomial conditional on the total number of flips), with a scan-corrected [5] Monte Carlo p-value when the phase offset is unknown. Applied to a representative L=11 run (η=0.9, γ=0.002, period 10, 60 phase bins, T max =10 7) we record N = 466,947 accepted injections and Y = 87 logical-Z flips (p 0 ≈ 1.863 × 10 −4 per accepted injection) and find no evidence of phase modulation at current statistics (sinusoid p ≈ 0.466; scan-corrected window p ≈ 0.694). We summarize power benchmarks (e.g. ≳ 700 flips to rule out ≥ 30% peak/trough modulation) and recommend reporting rules that prevent spurious phase effects in gated simulations and hardware-aligned experiments.
Periodic admission control (AC) can change when accepted events occur within a cycle even when long-run averages (e.g. total accepted injections per unit time) are unchanged. This "temporal bias" matters whenever logical-flip risk is phase-dependent or when analysts condition on accepted events without correcting for exposure. We formalize an exposure-proportional null for phase-resolved logical flips and propose two lightweight diagnostics: (i) a Poisson sinusoid regression on log-risk with an exposure offset, and (ii) an exact window-enrichment test (binomial conditional on the total number of flips), with a scan-corrected [5] Monte Carlo p-value when the phase offset is unknown. Applied to a representative L=11 run (η=0.9, γ=0.002, period 10, 60 phase bins, T max =10 7) we record N = 466,947 accepted injections and Y = 87 logical-Z flips (p 0 ≈ 1.863 × 10 −4 per accepted injection) and find no evidence of phase modulation at current statistics (sinusoid p ≈ 0.466; scan-corrected window p ≈ 0.694). We summarize power benchmarks (e.g. ≳ 700 flips to rule out ≥ 30% peak/trough modulation) and recommend reporting rules that prevent spurious phase effects in gated simulations and hardware-aligned experiments.
Surface-code continuous-time Markov chain (CTMC) models with boundary injection and sink absorption provide a continuous-time view of defect transport and logical-parity flips, but policy-gated injection introduces a normalization ambiguity: should flips be normalized by attempted or accepted injections? Standard discrete-round analyses and naive "flips per attempt" ratios do not separate throughput control from per-accepted-attempt maliciousness. We establish an exact renewal identity: under empty-manifold gating (accept only when the syndrome is empty), accepted injections launch disjoint excursions, and the hazard-normalized estimator peff,acc = N flip /A acc is unbiased for the odd-parity excursion probability under the accepted-start distribution (Theorem 1). A representative CTMC dataset at L = 11, η = 0.9 shows that peff,acc remains stable (within statistical error) even when the acceptance fraction varies by more than a factor of two, while "per attempted injection" ratios change proportionally (values reported in companion application paper). We provide portable bridges to practice: mapping sustaining flip rates to per-cycle logical error probability, a decoder-integration pipeline from CTMC logs to detection events, and a reduced-model exact cross-check. We do not claim an optimal admission policy, nor do we address non-renewal (overlap) regimes in this work.
Within the Stochastic Rupture (SR) framework, the only channel through which an external influence could act on quantum measurement without violating the elimination theorem for the Born rule is the rate of decoherence Γ, never the individual outcomes. This makes a concrete, falsifiable prediction available to test on existing hardware: a narrow spectral line in the time series of detection-event rates of a quantum error-correction (QEC) memory experiment. We perform such a search on the publicly released data of Google’s 105-qubit Willow surface-code memory experiments (Zenodo 13273331), analysing the r = 250 slice: 28 experiments (18 × d=3, 8 × d=5, 2 × d=7), 5 × 104 shots each, 1.4 × 106 shots in total, covering 22–451 kHz. The result is null. No frequency exceeds the Bonferronicorrected threshold zcrit = 3.76 in any per-distance or global stack, and no frequency shows z > 2 in more than five of the 28 experiments. The pipeline is not insensitive: it recovers three expected structures in the same data — a broadband low-frequency red-noise ramp (z falling monotonically from 27.7 to 6.0 over five contiguous bins), a coloured background ∼1.7× above shot noise from the code’s round-to-round detector correlations, and long memory across shots (HDFA = 0.632 ± 0.097, 0.757 ± 0.024, 0.771 ± 0.026 for d = 3, 5, 7). Calibrating by injection into the real data, where the response is quadratic (∆z = c a2) with c rising steeply with code distance, we set what is to our knowledge the first upper limit of this kind: any narrowband periodic modulation of Γ in the band 22–451 kHz has fractional amplitude a < 0.99% at 99% confidence. The negative result and its limit are reported as the primary deliverable; the search is intended to be repeated on the remaining 392 experiments and replicated on an independent dataset.
Abstract. Why a quantum measurement yields a single outcome has remained without direct experimental access for a century, largely because the question was considered interpretation-dependent and therefore untestable. We argue that the era of error-corrected logical qubits changes this status, and we identify the specific observable that makes it testable. First, we show that the postselection intrinsic to quantum error correction absorbs any event-level anomaly: hypothetical decision dynamics (objective collapse and allied mechanisms) can only manifest, on a logical register, through changes in functional laws rather than through individual events. Exactly two observables survive this filter — the coherence decay rate of a logical Greenberger-Horne-Zeilinger (GHZ) state and the syndrome acceptance rate. Second, we show that standard quantum mechanics predicts both observables to be strictly independent of the branch-amplitude imbalance w = |α|² − |β|² of the GHZ state, for all local Markovian noise channels. Third, a systematic inventory of the published record — spanning trapped ions, neutral atoms, superconducting and photonic platforms — shows that this imbalance has never been varied in any GHZ experiment, physical or logical. The amplitude axis of measurement dynamics is therefore experimentally virgin. Fourth, we specify a null-test protocol that requires only machine time on existing hardware: parity-oscillation scans at five imbalance values on logical GHZ states of N = 16 to 94 qubits, with and without postselection, at roughly 10⁴ shots per point, reaching slope sensitivities of about 10 % of the coherence decay rate and about 1 % absolute on the acceptance rate. A measured zero slope bounds all amplitude-coupled decision dynamics at values of N never before probed; a nonzero slope would constitute the first measured deviation from standard quantum dynamics on a macroscopic entangled register. We delineate precisely what such a test can and cannot decide, including a rigorously established indiscernibility class (Everett-type, hidden-variable, and retrocausal accounts) that no experiment of this kind can separate. The protocol is offered to all interested laboratories; its cost is machine time, not development. Preprint intended for journal submission (Phys. Rev. A / PRX Quantum). Companion record to OCU-IPC V10 (same Zenodo account). The enumeration programs referenced in Appendices A and B are included in this record. Contact: Denis Bernard phyborder838@gmail.com
Cryogenic control electronics accumulate systematic, non-zero-mean bias — from thermal cycling of mounts, flux leakage, and dielectric memory — that a feedback loop integrates until its actuator authority is exhausted and the integrator saturates. A controller that alarms on amplitude thresholds sees this failure only after correction is no longer available. This paper reports a precursor estimator that reads the dynamics of the control signal for the onset of systematic drift, built deliberately as a finite observer in the sense of the first Finite Cognition paper: a declared error budget, an explicit competence boundary, and fail-closed abstention. Its evidence is presented in two declared strata. First, a fresh, fully archived Monte-Carlo run of record on a declared control-loop model: across 30 seeds × 7 sensor-environment conditions × two drift polarities, with every threshold frozen before the batch, the estimator detected drift before saturation in 246/354 eligible collapse runs (69.5%, 95% interval 64.5–74.1%), with per-condition detection ranging from 25.5% (all disturbances combined) to 100% (dropout; 92.4–100), median leads of 7–17 s, and zero false interdicts across 210 healthy runs within the declared calibration window (0.0–1.8%) — a bound the long-horizon batch shows is conditional on the mandated recalibration schedule. Second, an archived read of live IBM quantum-hardware calibration telemetry (a 156-qubit Heron device, June 2026): the same governed detector family flagged the two genuinely degraded qubits and the sole sustained relaxation-time decline within that window (T_1 falling 88.0 → 19.1 µs across 43 returned calibration snapshots spanning 42 calendar days) — an event a longer archived record later resolves into the first, longest and deepest of four recurring excursions on the same qubit, at a cost to this detector family the paper states while staying silent on a bad-but-stable qubit and the 154 others. The estimator holds advisory-only authority under the programme's interface contract: it emits verdicts and writes nothing to the plant. This record supersedes an earlier version whose simulation table could not be traced to a quantum-specific run; the run of record reported here, code and data archived, is the evidence this paper stands on.
We explore the feasibility of fault-tolerant quantum computation using the bit-flip repetition code in a biased noise channel where only the bit-flip error can occur. While several logic gates can potentially produce phase-flip errors even in such a channel, we propose bias-preserving implementation of S , H , controlled- Z (CZ), and R z gates. We demonstrate that our scheme improves the computational precision in several tasks such as the time evolution of quantum systems and variational quantum eigensolver. Published by the American Physical Society 2024
Abstract Long-run quantum execution remains fundamentally constrained, not primarily by gate infidelity, but by cumulative instability of the rotating phase reference during runtime. While contemporary quantum control stacks rely on calibration, dynamical decoupling, and quantum error correction, these mechanisms operate reactively and assume that the underlying phase frame remains valid between interventions. This assumption breaks down as execution depth, runtime, and system size increase. This note reframes long-run execution failure as a phase-frame stability problem rather than a post-fault correction problem. Using empirical hardware-adjacent observations, it shows that longitudinal drift is structured, temporally correlated, and often collective across qubits, placing it outside the effective bandwidth of fast-noise suppression techniques. As a result, computation is frequently admitted under metastable conditions in which logical error amplification occurs despite unchanged physical gate metrics. Based on this empirical and structural analysis, the note identifies a missing architectural element: a preventive drift-bounding layer that constrains phase-frame deviation before execution proceeds. The argument is intentionally architectural rather than implementational. No hardware-specific parameters, algorithms, or corrective primitives are disclosed. The purpose of this document is to establish why scalable quantum execution requires preventive phase stabilization at the execution boundary, and why reactive correction alone cannot remove this limitation. Detailed theoretical foundations, validation pathways, and hardware-compatible realizations exist but are intentionally excluded from this public note.