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Measuring Entangled Qutrits and Their Use for Quantum Bit Commitment

Nathan K. Langford·Rohan B. Dalton·Michael D. Harvey·Jeremy L. O'Brien·Geoffrey J. Pryde·Alexei Gilchrist·Stephen D. Bartlett·Andrew G. White
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Abstract

We produce and holographically measure entangled qudits encoded in transverse spatial modes of single photons. With the novel use of a quantum state tomography method that only requires two-state superpositions, we achieve the most complete characterisation of entangled qutrits to date. Ideally, entangled qutrits provide better security than qubits in quantum bit-commitment: we model the sensitivity of this to mixture and show experimentally and theoretically that qutrits with even a small amount of decoherence cannot offer increased security over qubits.

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Nathan K. Langford, Rohan B. Dalton, Michael D. Harvey, Jeremy L. O'Brien, Geoffrey J. Pryde, Alexei Gilchrist, Stephen D. Bartlett, Andrew G. White. 2004-08-14. Measuring Entangled Qutrits and Their Use for Quantum Bit Commitment. https://doi.org/10.1103/physrevlett.93.053601

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