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Quantum Cryptography using entangled photons in energy-time Bell states

W. Tittel·J. Brendel·H. Zbinden·N. Gisin
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Abstract

We present a setup for quantum cryptography based on photon pairs in energy-time Bell states and show its feasability in a laboratory experiment. Our scheme combines the advantages of using photon pairs instead of faint laser pulses and the possibility to preserve energy-time entanglement over long distances. Moreover, using 4-dimensional energy-time states, no fast random change of bases is required in our setup : Nature itself decides whether to measure in the energy or in the time base.

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W. Tittel, J. Brendel, H. Zbinden, N. Gisin. 1999-11-25. Quantum Cryptography using entangled photons in energy-time Bell states. https://doi.org/10.1103/physrevlett.84.4737

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