Structural Protection of GHZ States: Cross-Platform Validation with 9-Qubit Scaling (v4.1)

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: 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 (ibmfez): 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%