6.5 Conference Key Agreement with Single Photon Interference
103
of detectors implies a higher probability of dark counts, which is another source of
error manifesting itself at high losses with a drop of the key rate.
As anticipated, Fig. 6.5 clearly shows the significant improvement in the conference key rate when employing our CKA based on single-photon interference,
as opposed to employing a GHZ-state-based CKA like the N -party BB84 protocol.
Moreover, due to the improved scaling with the loss, the CKA key rate (6.37) also surpasses the direct-transmission bound (6.40) for sufficiently long distances, similarly
to what happens with the TF-QKD protocol and the PLOB bound (see Fig. 6.2).
References
1. Takeoka, M., Guha, S., & Wilde, M. M. (2014). Fundamental rate-loss tradeoff for optical
quantum key distribution. Nature Communications, 5(1), 5235.
2. Pirandola, S., Laurenza, R., Ottaviani, C., & Banchi, L. (2017). Fundamental limits of repeaterless quantum communications. Nature Communications, 8(1), 15043.
3. Briegel, H.-J., Dür, W., Cirac, J. I., & Zoller, P. (1998). Quantum repeaters: The role of imperfect
local operations in quantum communication. Physical Review Letters, 81, 5932–5935.
4. Sangouard, N., Simon, C., de Riedmatten, H., & Gisin, N. (2011). Quantum repeaters based
on atomic ensembles and linear optics. Reviews of Modern Physics, 83, 33–80.
5. Duan, L.-M., Lukin, M. D., Cirac, J. I., & Zoller, P. (2001). Long-distance quantum communication with atomic ensembles and linear optics. Nature, 414(6862), 413–418.
6. Mazurek, P., Grudka, A., Horodecki, M., Horodecki, P., Łodyga, J., Pankowski, L., et al. (2014).
Long-distance quantum communication over noisy networks without long-time quantum memory. Physical Review A, 90, 062311.
7. Munro, W. J., Stephens, A. M., Devitt, S. J., Harrison, K. A., & Nemoto, K. (2012). Quantum
communication without the necessity of quantum memories. Nature Photonics, 6(11), 777–
781.
8. Azuma, K., Tamaki, K., & Lo, H.-K. (2015). All-photonic quantum repeaters. Nature Communications, 6(1), 6787.
9. Panayi, C., Razavi, M., Ma, X., & Lütkenhaus, N. (2014). Memory-assisted measurementdevice-independent quantum key distribution. New Journal of Physics, 16(4), 043005.
10. Abruzzo, S., Kampermann, H., & Bruß, D. (2014). Measurement-device-independent quantum
key distribution with quantum memories. Physical Review A, 89, 012301.
11. Azuma, K., Tamaki, K., & Munro, W. J. (2015). All-photonic intercity quantum key distribution.
Nature Communications, 6(1), 10171.
12. Lucamarini, M., Yuan, Z. L., Dynes, J. F., & Shields, A. J. (2018). Overcoming the rate-distance
limit of quantum key distribution without quantum repeaters. Nature, 557(7705), 400–403.
13. Curty, M., Azuma, K., & Lo, H. -K. (2019). Simple security proof of twin-field type quantum
key distribution protocol. npj Quantum Information, 5(1), 64.
14. Cui, C., Yin, Z.-Q., Wang, R., Chen, W., Wang, S., Guo, G.-C., et al. (2019). Twin-field quantum
key distribution without phase postselection. Physical Review Applied, 11, 034053.
15. Lin, J., & Lütkenhaus, N. (2018). Simple security analysis of phase-matching measurementdevice-independent quantum key distribution. Physical Review A, 98, 042332.
16. Ma, X., Zeng, P., & Zhou, H. (2018). Phase-matching quantum key distribution. Physical
Review X, 8, 031043.
17. Wang, X.-B., Yu, Z.-W., & Hu, X.-L. (2018). Twin-field quantum key distribution with large
misalignment error. Physical Review A, 98, 062323.
18. Wang, S., He, D.-Y., Yin, Z.-Q., Lu, F.-Y., Cui, C.-H., Chen, W., et al. (2019). Beating the fundamental rate-distance limit in a proof-of-principle quantum key distribution system. Physical
Review X, 9, 021046.
103
of detectors implies a higher probability of dark counts, which is another source of
error manifesting itself at high losses with a drop of the key rate.
As anticipated, Fig. 6.5 clearly shows the significant improvement in the conference key rate when employing our CKA based on single-photon interference,
as opposed to employing a GHZ-state-based CKA like the N -party BB84 protocol.
Moreover, due to the improved scaling with the loss, the CKA key rate (6.37) also surpasses the direct-transmission bound (6.40) for sufficiently long distances, similarly
to what happens with the TF-QKD protocol and the PLOB bound (see Fig. 6.2).
References
1. Takeoka, M., Guha, S., & Wilde, M. M. (2014). Fundamental rate-loss tradeoff for optical
quantum key distribution. Nature Communications, 5(1), 5235.
2. Pirandola, S., Laurenza, R., Ottaviani, C., & Banchi, L. (2017). Fundamental limits of repeaterless quantum communications. Nature Communications, 8(1), 15043.
3. Briegel, H.-J., Dür, W., Cirac, J. I., & Zoller, P. (1998). Quantum repeaters: The role of imperfect
local operations in quantum communication. Physical Review Letters, 81, 5932–5935.
4. Sangouard, N., Simon, C., de Riedmatten, H., & Gisin, N. (2011). Quantum repeaters based
on atomic ensembles and linear optics. Reviews of Modern Physics, 83, 33–80.
5. Duan, L.-M., Lukin, M. D., Cirac, J. I., & Zoller, P. (2001). Long-distance quantum communication with atomic ensembles and linear optics. Nature, 414(6862), 413–418.
6. Mazurek, P., Grudka, A., Horodecki, M., Horodecki, P., Łodyga, J., Pankowski, L., et al. (2014).
Long-distance quantum communication over noisy networks without long-time quantum memory. Physical Review A, 90, 062311.
7. Munro, W. J., Stephens, A. M., Devitt, S. J., Harrison, K. A., & Nemoto, K. (2012). Quantum
communication without the necessity of quantum memories. Nature Photonics, 6(11), 777–
781.
8. Azuma, K., Tamaki, K., & Lo, H.-K. (2015). All-photonic quantum repeaters. Nature Communications, 6(1), 6787.
9. Panayi, C., Razavi, M., Ma, X., & Lütkenhaus, N. (2014). Memory-assisted measurementdevice-independent quantum key distribution. New Journal of Physics, 16(4), 043005.
10. Abruzzo, S., Kampermann, H., & Bruß, D. (2014). Measurement-device-independent quantum
key distribution with quantum memories. Physical Review A, 89, 012301.
11. Azuma, K., Tamaki, K., & Munro, W. J. (2015). All-photonic intercity quantum key distribution.
Nature Communications, 6(1), 10171.
12. Lucamarini, M., Yuan, Z. L., Dynes, J. F., & Shields, A. J. (2018). Overcoming the rate-distance
limit of quantum key distribution without quantum repeaters. Nature, 557(7705), 400–403.
13. Curty, M., Azuma, K., & Lo, H. -K. (2019). Simple security proof of twin-field type quantum
key distribution protocol. npj Quantum Information, 5(1), 64.
14. Cui, C., Yin, Z.-Q., Wang, R., Chen, W., Wang, S., Guo, G.-C., et al. (2019). Twin-field quantum
key distribution without phase postselection. Physical Review Applied, 11, 034053.
15. Lin, J., & Lütkenhaus, N. (2018). Simple security analysis of phase-matching measurementdevice-independent quantum key distribution. Physical Review A, 98, 042332.
16. Ma, X., Zeng, P., & Zhou, H. (2018). Phase-matching quantum key distribution. Physical
Review X, 8, 031043.
17. Wang, X.-B., Yu, Z.-W., & Hu, X.-L. (2018). Twin-field quantum key distribution with large
misalignment error. Physical Review A, 98, 062323.
18. Wang, S., He, D.-Y., Yin, Z.-Q., Lu, F.-Y., Cui, C.-H., Chen, W., et al. (2019). Beating the fundamental rate-distance limit in a proof-of-principle quantum key distribution system. Physical
Review X, 9, 021046.