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: <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%