Three-qubit GHZ state preparation (references arXiv:2607.13645)

Primitive: multi-qubit GHZ state preparation. This card builds the canonical three-qubit GHZ state (|000> + |111|)/sqrt(2) with a Hadamard followed by a CNOT ladder, the minimal genuinely-multipartite instance of the family the paper studies.

The referenced paper, Effects of coherent and incoherent measurement imperfections on multipartite quantum nonlocality and quantum key distribution (arXiv:2607.13645), analyses how coherent angular misalignment and incoherent outcome flipping affect Bell-value degradation and nonlocality thresholds in n-partite GHZ states, using the Mermin, Svetlichny and Mermin-Ardehali-Belinskii-Klyshko (MABK) inequalities. Per its abstract, the authors report that coherent misalignment produces periodic angular violation windows whose widths shrink with the number of parties, while incoherent outcome flipping yields a single critical flipping probability that behaves differently across the inequalities, and they connect the degraded Bell values to Devetak-Winter key-rate bounds under a convex-combination attack model.

This Provenova card does not reproduce any of those results. It is a deterministic, noiseless statevector simulation of the GHZ state-preparation circuit only, run on Provenova's simulator; it does not model the measurement imperfections, Bell inequalities, or key-rate analysis of the paper, and no hardware is involved. The idealised run yields the expected outcome: the two outcomes 000 and 111 each carry probability 1/2 and all others vanish. This card references the paper as the inspiration for the primitive and does not imply any endorsement by its authors.