High-speed linear optics quantum computing using active feed-forward

Abstract

As information carriers in quantum computing1, photonic qubits have the advantage of undergoing negligible decoherence. However, the absence of any significant photon–photon interaction is problematic for the realization of non-trivial two-qubit gates. One solution is to introduce an effective nonlinearity by measurements resulting in probabilistic gate operations2,3. In one-way quantum computation4,5,6,7,8, the random quantum measurement error can be overcome by applying a feed-forward technique, such that the future measurement basis depends on earlier measurement results. This technique is crucial for achieving deterministic quantum computation once a cluster state (the highly entangled multiparticle state on which one-way quantum computation is based) is prepared. Here we realize a concatenated scheme of measurement and active feed-forward in a one-way quantum computing experiment. We demonstrate that, for a perfect cluster state and no photon loss, our quantum computation scheme would operate with good fidelity and that our feed-forward components function with very high speed and low error for detected photons. With present technology, the individual computational step (in our case the individual feed-forward cycle) can be operated in less than 150 ns using electro-optical modulators. This is an important result for the future development of one-way quantum computers, whose large-scale implementation will depend on advances in the production and detection of the required highly entangled cluster states.

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Figure 1: Schematic drawing of the experimental set-up.
Figure 2: Active feed-forward of two different single-qubit rotations.
Figure 3: Feed-forward of a two-qubit operation.
Figure 4: Demonstration of Grover’s search algorithm with feed-forward.

References

  1. 1

    Bennett, C. & DiVicenzo, D. Quantum information and computation. Nature 404, 247–255 (2000)

  2. 2

    Knill, E., Laflamme, R. & Milburn, G. J. A scheme for efficient quantum computation with linear optics. Nature 409, 46–52 (2001)

  3. 3

    Gottesman, D. & Chuang, I. L. Demonstrating the viability of universal quantum computation using teleportation and single-qubit operations. Nature 402, 390–393 (1999)

  4. 4

    Briegel, H. J. & Raussendorf, R. Persistent entanglement in arrays of interacting particles. Phys. Rev. Lett. 86, 910–913 (2001)

  5. 5

    Raussendorf, R. & Briegel, H. J. A one-way quantum computer. Phys. Rev. Lett. 86, 5188–5191 (2001)

  6. 6

    Raussendorf, R., Brown, D. E. & Briegel, H. J. The one-way quantum computer – a non-network model of quantum computation. J. Mod. Opt. 49, 1299–1306 (2002)

  7. 7

    Nielsen, M. Optical quantum computation using cluster states. Phys. Rev. Lett. 93, 040503 (2004)

  8. 8

    Aliferis, P. & Leung, D. Computation by measurements: A unifying picture. Phys. Rev. A 70, 062314 (2004)

  9. 9

    Walther, P. et al. Experimental one-way quantum computing. Nature 434, 169–176 (2005)

  10. 10

    Kiesel, N. et al. Experimental analysis of a four-qubit photon cluster state. Phys. Rev. Lett. 95, 210502 (2005)

  11. 11

    Zhang, A. N. et al. Experimental construction of optical multiqubit cluster states from Bell states. Phys. Rev. A 73, 022330 (2006)

  12. 12

    Pittman, T. B., Jacobs, B. C. & Franson, J. D. Demonstration of feed-forward control for linear optics quantum computation. Phys. Rev. A 66, 052305 (2002)

  13. 13

    Giacomini, S., Sciarrino, F., Lombardi, E. & DeMartini, F. Active teleportation of a quantum bit. Phys. Rev. A 66, 030302 (2002)

  14. 14

    Ursin, R. et al. Quantum teleportation link across the Danube. Nature 430, 849 (2004)

  15. 15

    Grover, L. K. Quantum mechanics helps in search for a needle in a haystack. Phys. Rev. Lett. 79, 325–328 (1997)

  16. 16

    White, A. G., James, D. F. V., Eberhard, P. H. & Kwiat, P. G. Nonmaximally entangled states: production, characterization, and utilization. Phys. Rev. Lett. 83, 3103–3107 (1999)

  17. 17

    James, D., Kwiat, P., Munro, W. & White, A. Measurement of qubits. Phys. Rev. A 64, 052312 (2001)

  18. 18

    Toth, G. & Gühne, O. Detecting genuine multipartite entanglement with two local measurements. Phys. Rev. Lett. 94, 060501 (2005)

  19. 19

    Riebe, M. et al. Deterministic quantum teleportation with atoms. Nature 429, 734–737 (2004)

  20. 20

    Barrett, M. D. et al. Deterministic quantum teleportation of atomic qubits. Nature 429, 737–739 (2004)

  21. 21

    Vandersypen, L. M. K. et al. Experimental realization of Shor’s quantum factoring algorithm using nuclear magnetic resonance. Nature 414, 883–887 (2001)

  22. 22

    Nielsen, M. & Chuang, I. L. Quantum Compuation and Quantum Information (Cambridge Univ. Press, Cambridge, UK, 2000)

  23. 23

    Nielsen, M. Journal club notes on the cluster-state model of quantum computation. 〈http://www.qinfo.org/qc-by-measurement/cluster-state.pdf〉 (2003)

  24. 24

    Coffman, V., Kundu, J. & Wootters, W. K. Distributed entanglement. Phys. Rev. A 61, 052306 (2000)

  25. 25

    Horodecki, R., Horodecki, P. & Horodecki, M. Violating Bell inequality by mixed spin-1/2 states: necessary and sufficient condition. Phys. Lett. A 200, 340–344 (1995)

  26. 26

    Shor, P. W. in Proc. 35th Annual Symp. on Foundations of Computer Science (ed. Goldwasser, S.) 124–134 (IEEE Computer Society Press, Los Alamitos, 1994)

  27. 27

    Ahn, J., Weinacht, T. C. & Bucksbaum, P. H. Information storage and retrieval through quantum phase. Science 287, 463–465 (2000)

  28. 28

    Raussendorf, R., Browne, D. E. & Briegel, H. J. Measurement-based quantum computation on cluster states. Phys. Rev. A 68, 022312 (2003)

  29. 29

    Hein, M., Eisert, J. & Briegel, H. J. Multi-party entanglement in graph states. Phys. Rev. A 69, 062311 (2004)

  30. 30

    Soudagar, Y. et al. Cluster state quantum computing in optical fibres. Preprint at 〈http://arxiv.org/quant-ph/0605111〉 (2006)

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Acknowledgements

We are grateful to M. Aspelmeyer, Č. Brukner, J. I. Cirac, J. Kofler and K. Resch for discussions as well as to T. Bergmann and G. Mondl for assistance with the electronics. R.P. thanks E.-M. Röttger for assistance in the laboratory. We acknowledge financial support from the Austrian Science Fund (FWF), the European Commission under the Integrated Project Qubit Applications (QAP) funded by the IST directorate and the DTO-funded US Army Research Office.

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Correspondence to Robert Prevedel or Anton Zeilinger.

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Prevedel, R., Walther, P., Tiefenbacher, F. et al. High-speed linear optics quantum computing using active feed-forward. Nature 445, 65–69 (2007). https://doi.org/10.1038/nature05346

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