W State Witness
Three qubits share exactly one excitation — no one knows which holds it. Click measure to collapse the W state and watch where the single |1⟩ lands. Inspired by Osaka University's May 2026 real-time W state detection breakthrough.
Measurements
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q₀ → |1⟩
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q₁ → |1⟩
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q₂ → |1⟩
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Preparation circuit
The science: A W state spreads a single photon equally across three qubits: |W⟩ = (|100⟩ + |010⟩ + |001⟩)/√3. Unlike GHZ states, losing one qubit leaves the other two still entangled — making W states fundamentally more robust for quantum repeater networks. Osaka University's 2026 breakthrough uses photon-number-resolving detectors to verify W states in real time, a key milestone toward fault-tolerant long-distance quantum communication.