Verify quantum states faster than full tomography — fewer circuits, same confidence
3^n Pauli basis measurements
81
Circuits
—
Total Shots
—
Run Cost
—
Time
Only 2 circuits needed
2
Circuits
—
Total Shots
—
Run Cost
—
Time
TomoGate determines whether a prepared quantum state exceeds a target fidelity threshold. It does not estimate the full quantum state, but it provably reaches the same accept/reject decision as full tomography for GHZ-class states.
To fully characterize an n-qubit quantum state, you need to measure in 3^n different Pauli bases (X, Y, Z combinations). For 4 qubits, that's 81 circuits.
Reference: Quantum State Tomography (Nielsen & Chuang)
TomoGate uses an efficient fidelity validation approach to determine if a GHZ state exceeds a fidelity threshold using dramatically fewer measurement circuits. Same decision, orders of magnitude fewer shots.
Based on published witness protocols for structured quantum states.
Hardware validated Feb 11, 2026 (job d66eomdbujdc73culfc0). 78 calibration runs (Jan-Feb 2026) + fresh GHZ-4 witness on IBM Fez.
TomoGate uses efficient GHZ state validation to determine whether downstream quantum workloads should proceed or abort. This validation requires only 2 measurement circuits, compared to 81 circuits for full state tomography.
78
Calibration runs
93%
Classification accuracy
100%
Recall (no missed failures)
2
Circuits needed
| Backend | Protocol | Fidelity | Decision | Outcome |
|---|---|---|---|---|
| IBM Fez | GHZ-4 witness (4K shots) | F = 0.837 | VIABLE | Pipeline proceeds (pop=0.857, coh=0.817) |
| IBM Fez | 78-run aggregate | 93% correct | VALIDATED | Consistent over 2 months |
| Rigetti Ankaa-3 | GHZ-4 witness | Below threshold | DOOMED | Abort saves credits |
When fidelity falls below the configured policy input, TomoGate fails closed and aborts execution — preventing wasted QPU credits before expensive downstream workloads begin. Across 78 calibration runs, TomoGate caught 100% of below-threshold states (zero missed failures).
Decision labels (VIABLE/DOOMED) map to the universal ALLOW/ABORT model. Results reflect real QPU behavior and may change as hardware is recalibrated.
No. TomoGate certifies whether a GHZ state exceeds a fidelity threshold. Full density matrix reconstruction is not performed.
Full tomography is required when complete state reconstruction or error decomposition is needed. QubitBoost is intended for fast validation, calibration checks, and repeated production runs.
This demo validates GHZ states, but the gating principle extends to other structured quantum states.
Full state tomography requires measurements in all 3ⁿ Pauli bases to reconstruct the density matrix. For GHZ states, TomoGate uses fast state verification to provably certify whether fidelity exceeds a threshold using dramatically fewer measurement circuits. This reaches the same accept/reject decision with orders-of-magnitude fewer resources.