Version 4.0: Definitive experimental validation of structural coherence protection (N2) in GHZ entangled states across five quantum computing platforms. KEY RESULTS:- IonQ Forte: +7.27% GHZ advantage over product states (p = 7.17×10⁻²⁷, Cohen's d = 6.11)- IBM Heron: 2.4–13.8× slower decay for GHZ vs product states- Rigetti Ankaa-3, IQM Garnet, IQM Emerald: No N2 detected (negative controls) MAIN FINDINGS:1. N2 is real and statistically incontrovertible (p << 5σ particle physics standard)2. N2 is cross-platform: confirmed on superconducting (IBM) and trapped-ion (IonQ) technologies3. N2 requires high-fidelity hardware: >99.5% 2Q gate fidelity threshold4. N2 is GHZ-specific: W-states and Cluster states show no protection5. Negative results on Rigetti/IQM provide mechanistic insight into fidelity thresholds PLATFORMS TESTED:- IBM Heron (ibm_torino, ibm_fez, ibm_boston)- IonQ Forte 1 (trapped ions, 36 qubits)- Rigetti Ankaa-3 (84 qubits)- IQM Garnet (20 qubits)- IQM Emerald (5 qubits) Total experimental investment: ~$3,700 USD This version incorporates Panel Cerezo methodology recommendations and extends v3.1 (DOI: 10.5281/zenodo.18291164) with definitive statistical analysis meeting all rigor criteria. Experiment dates: January 15-19, 2026
Version 4.0: Definitive experimental validation of structural coherence protection (N2) in GHZ entangled states across five quantum computing platforms. KEY RESULTS:- IonQ Forte: +7.27% GHZ advantage over product states (p = 7.17×10⁻²⁷, Cohen's d = 6.11)- IBM Heron: 2.4–13.8× slower decay for GHZ vs product states- Rigetti Ankaa-3, IQM Garnet, IQM Emerald: No N2 detected (negative controls) MAIN FINDINGS:1. N2 is real and statistically incontrovertible (p << 5σ particle physics standard)2. N2 is cross-platform: confirmed on superconducting (IBM) and trapped-ion (IonQ) technologies3. N2 requires high-fidelity hardware: >99.5% 2Q gate fidelity threshold4. N2 is GHZ-specific: W-states and Cluster states show no protection5. Negative results on Rigetti/IQM provide mechanistic insight into fidelity thresholds PLATFORMS TESTED:- IBM Heron (ibm_torino, ibm_fez, ibm_boston)- IonQ Forte 1 (trapped ions, 36 qubits)- Rigetti Ankaa-3 (84 qubits)- IQM Garnet (20 qubits)- IQM Emerald (5 qubits) Total experimental investment: ~$3,700 USD This version incorporates Panel Cerezo methodology recommendations and extends v3.1 (DOI: 10.5281/zenodo.18291164) with definitive statistical analysis meeting all rigor criteria. Experiment dates: January 15-19, 2026
Version 4.1 PLATINUM: Extended validation of structural coherence protection (N2) in GHZ entangled states, now including 9-qubit scaling results across two fundamentally different quantum technologies. KEY BREAKTHROUGH - TECHNOLOGY INDEPENDENCE:- IBM Heron (9q): +51.75% GHZ advantage (GHZ 52.05% vs Product 0.30%)- IonQ Forte (9q): +50.12% GHZ advantage (GHZ 83.00% vs Product 32.88%)- Cross-platform difference: <2% This near-identical convergence (~50%) across superconducting transmons and trapped ions strongly suggests N2 is a fundamental property of GHZ topology under dephasing-dominated noise, not a hardware artifact. PLATINUM HIGHLIGHTS:- Protection ratio ~173× on IBM Heron at maximum stress (4000 dt)- N2 persists across scaling: 5q (+7.23%), 7q (+4.88%), 9q (+50.12%) on IonQ- Statistical foundation: p = 7.17×10⁻²⁷ at 5 qubits (from v4.0) FIVE DEFINITIVE FINDINGS:1. N2 is real and scales to 9 qubits2. N2 is technology-independent (~50% in both superconducting and trapped-ion systems)3. N2 requires high-fidelity hardware (>99.5% 2Q gate fidelity threshold)4. N2 is GHZ-specific (W-states and Cluster states show no protection)5. N2 is statistically incontrovertible PLATFORMS TESTED:- IBM Heron r2 (ibm_fez): 3-9 qubits ✓- IonQ Forte 1: 3-9 qubits ✓- Rigetti Ankaa-3: 5 qubits ✗ (low fidelity)- IQM Garnet: 5 qubits ✗ (low fidelity)- IQM Emerald: 5 qubits ✗ (low fidelity) Total experimental investment: ~$3,800 USDExperiment dates: January 16-19, 2026 This version extends v4.0 (DOI: 10.5281/zenodo.18295213) with 9-qubit PLATINUM results demonstrating cross-platform convergence. "Two dragons of different technologies, tamed by the same physics"IBM Heron: +51.75% | IonQ Forte: +50.12% | Difference: <2%
Version 3.1: Extended cross-platform validation of structural coherence protection in GHZ entangled states. KEY FINDINGS:- GHZ states show 2.4-13.8× slower decay (IBM Heron) and +5-9% fidelity advantage (IonQ Forte) vs product states- Structural protection is GHZ-specific: W-states (-12%) and Cluster states (-38%) underperform product states on IonQ- Non-Markovian memory (N1) detected in trapped ions: Dynamical decoupling with Z-pulses improves GHZ protection by +2.99%, 5× stronger than IBM's +0.6%- Scaling confirmed from 3 to 7 qubits with 100% consistency across all measurements PLATFORMS:- IBM Heron: ibm_torino (r1), ibm_fez (r2), ibm_boston (r3)- IonQ Forte 1 (trapped ions, 36 qubits) EXPERIMENT DATES: January 15-18, 2026TOTAL INVESTMENT: ~$2,350 USD (IBM + AWS/IonQ) This version extends v2.1 (DOI: 10.5281/zenodo.18284373) with IonQ cross-platform validation, entanglement-type dependence analysis, and non-Markovian memory detection via dynamical decoupling.
Version 2.1: Extended experimental analysis comparing coherence decay of GHZ, W, and product states on IBM Heron quantum processors (r1, r2, r3). Key findings:- GHZ states decay 2.4–13.8× slower than product states across three processor generations- Dynamical decoupling with virtual Z-pulses (DD-Z) provides marginal improvement (+0.6%), while physical X-pulses (DD-X) degrade coherence by -24.4%- W-state performance is architecture-dependent: superior on r1/r3, inferior on r2- Weak non-Markovian noise signatures detected at 5 µs delay window This version extends v1.0 (DOI: 10.5281/zenodo.18274447) with W-state analysis, comprehensive DD protocol testing, and the DD-Z vs DD-X discovery. Backends: ibm_torino (r1), ibm_fez (r2), ibm_boston (r3)Configuration: 3-5 qubits, 4000 shots, delays 0-100,000 dt
We report experimental measurements comparing the coherence decay of three-qubit Greenberger-Horne-Zeilinger (GHZ) entangled states versus locally coherent product states (|+++⟩) under idle time evolution on IBM Heron quantum processors. Across three different processor generations (Heron r1, r2, r3), we consistently observe that the GHZ state maintains higher fidelity than the product state as idle delay increases. Decay rate analysis reveals that |+++⟩ decays 2.4–13.8× faster than GHZ depending on the backend. A control experiment with |000⟩ confirms the decay mechanism is dominated by dephasing (T₂-type noise) rather than energy relaxation (T₁) or readout errors. These results demonstrate a structural dependence of coherence stability on the topology of the quantum state. Backends: ibm_fez (Heron r2), ibm_torino (Heron r1), ibm_boston (Heron r3)Configuration: 3 qubits, 4000 shots, 20 repetitions per delay pointDelays: 0, 500, 1000, 2000, 4000 dt
Eight verified quantum computing jobs executed on IBM Quantum hardware (ibm_fez Heron R2, 156 qubits; ibm_torino Heron R1, 133 qubits) between January 27 and March 15, 2026. User ID: IBMid-692001DJRD. Experiments include: 1. Bell State Entanglement — 96.3% fidelity on ibm_fez Heron R2 (Concurrence C = 0.926, Tangle T = 0.858, 1,000 shots). Cross-platform benchmark: Heron R2 vs Heron R1 (+8.3 pp fidelity advantage, noise ratio 2.43×). 2. Reproducibility Test — Two independent runs of identical circuit (χ² = 2.70, p = 0.44, df = 3). H₀ not rejected: statistically indistinguishable results at 95% confidence. 3. BB84 Quantum Key Distribution — Full Alice/Eve/Bob protocol implementation. Alice baseline error 0.60% → Bob QBER 49.0% under eavesdropping (82× degradation). Experimental demonstration of the quantum no-cloning theorem. Control group design isolates eavesdropper signal from hardware noise baseline. 4. Variational Quantum Circuit (VQC) — 2-qubit circuit, 10 trained parameters with tied weights (θ₃ = θ₄), 8 CZ gates in 4 entangling layers. 4-qubit ansatz: Shannon entropy 3.885/4.000 bits (97.1%), ground-state bias confirmed (χ² = 300.94, p ≈ 0). 5. Quantum Random Number Generation (QRNG) — 8-bit outputs, 10/10 unique values per shot (range 16–254). Total: 39,010 quantum measurements across 8 jobs and 10 circuits. QPU time: 4.8 seconds. Job completion rate: 100%. All results decoded from raw IBM SamplerV2 BitArray binary archives (zlib + base64 + NumPy .npy pipeline). No simulations. Statistical validation applied throughout (Wilson 95% CIs, chi-squared tests). Stack: Qiskit Runtime SamplerV2 · QPY · OpenQASM 2.0 · Python · NumPy · SciPy Repository: https://github.com/dinohatibovicWhitepaper: https://dinohatibovic.github.io (Doc QAI-WP-2026-01-28-V4)
We provide a minimal analytic framework, entirely within standard open-quantum-system theory, that explains the protocol-robust GHZ advantage observed experimentally across heterogeneous quantum platforms. The framework rests on three results: (1) the Hamming Decay Theorem, showing that off-diagonal density matrix elements decay as lambda^{d_H} under any local quantum channel; (2) a binomial derivation of the product-state fidelity F_prod = [(1+exp(-gamma*t))/2]^N under the IBM protocol; and (3) a unification of the two experimental regimes (IBM dephasing-dominated and IonQ amplitude-damping-dominated) via T2-blindness of the GHZ observable. A three-parameter noise model calibrated to IonQ 5-qubit data reproduces the selectivity pattern GHZ+, W-, Cluster- with correct signs. The structural invariant S(rho) captures the channel-independent topology underlying the advantage. Includes Appendix A: Revised Empirical Basis with cross-platform convergence data, selectivity tables, hardware threshold, and kill switches.