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Quantum key distribution with higher-order alphabets using spatially-encoded qudits

S. P. Walborn·D. S. Lemelle·M. P. Almeida·P. H. Souto Ribeiro
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Abstract

We propose and demonstrate a quantum key distribution scheme in higher-order $d$-dimensional alphabets using spatial degrees of freedom of photons. Our implementation allows for the transmission of 4.56 bits per sifted photon, while providing improved security: an intercept-resend attack on all photons would induce an error rate of 0.47. Using our system, it should be possible to send more than a byte of information per sifted photon.

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S. P. Walborn, D. S. Lemelle, M. P. Almeida, P. H. Souto Ribeiro. 2006-03-10. Quantum key distribution with higher-order alphabets using spatially-encoded qudits. https://doi.org/10.1103/physrevlett.96.090501

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