Quantum gates and memory using microwave-dressed states

Abstract

Trapped atomic ions have been used successfully to demonstrate1 basic elements of universal quantum information processing. Nevertheless, scaling up such methods to achieve large-scale, universal quantum information processing (or more specialized quantum simulations2,3,4,5) remains challenging. The use of easily controllable and stable microwave sources, rather than complex laser systems6,7, could remove obstacles to scalability. However, the microwave approach has drawbacks: it involves the use of magnetic-field-sensitive states, which shorten coherence times considerably, and requires large, stable magnetic field gradients. Here we show how to overcome both problems by using stationary atomic quantum states as qubits that are induced by microwave fields (that is, by dressing magnetic-field-sensitive states with microwave fields). This permits fast quantum logic, even in the presence of a small (effective) Lamb–Dicke parameter (and, therefore, moderate magnetic field gradients). We experimentally demonstrate the basic building blocks of this scheme, showing that the dressed states are long lived and that coherence times are increased by more than two orders of magnitude relative to those of bare magnetic-field-sensitive states. This improves the prospects of microwave-driven ion trap quantum information processing, and offers a route to extending coherence times in all systems that suffer from magnetic noise, such as neutral atoms, nitrogen-vacancy centres, quantum dots or circuit quantum electrodynamic systems.

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Figure 1: Microwave-dressed qubit states.
Figure 2: Lifetime of the dressed state | D 〉.
Figure 3: Single-qubit gates with dressed states.
Figure 4: Multiqubit scheme for three ions exposed to a magnetic field gradient.

References

  1. 1

    Blatt, R. & Wineland, D. Entangled states of trapped atomic ions. Nature 453, 1008–1015 (2008)

    ADS  CAS  Article  Google Scholar 

  2. 2

    Friedenauer, A. Schmitz, H. Glueckert, J. T., Porras, D. & Schaetz, T. Simulating a quantum magnet with trapped ions. Nature Phys. 4, 757–761 (2008)

    ADS  CAS  Article  Google Scholar 

  3. 3

    Kim, K. et al. Quantum simulation of frustrated Ising spins with trapped ions. Nature 465, 590–593 (2010)

    ADS  CAS  Article  Google Scholar 

  4. 4

    Gerritsma, R. et al. Quantum simulation of the Dirac equation. Nature 463, 68–71 (2010)

    ADS  CAS  Article  Google Scholar 

  5. 5

    Johanning, M. Varón, A. F. & Wunderlich, C. Quantum simulations with cold trapped ions. J. Phys. B 42, 154009 (2009)

    ADS  Article  Google Scholar 

  6. 6

    Mintert, F. & Wunderlich, C. Ion-trap quantum logic using long-wavelength radiation. Phys. Rev. Lett. 87, 257904 (2001)

    ADS  CAS  Article  Google Scholar 

  7. 7

    Ospelkaus, C. et al. Trapped-ion quantum logic gates based on oscillating magnetic fields. Phys. Rev. Lett. 101, 090502 (2008)

    ADS  CAS  Article  Google Scholar 

  8. 8

    Ozeri, R. et al. Errors in trapped-ion quantum gates due to spontaneous photon scattering. Phys. Rev. A 75, 042329 (2007)

    ADS  Article  Google Scholar 

  9. 9

    Plenio, M. B. & Knight, P. L. Decoherence limits to quantum computation using trapped ions. Proc. R. Soc. Lond. A 453, 2017–2041 (1997)

    ADS  CAS  Article  Google Scholar 

  10. 10

    Sørensen, A. & Mølmer, K. Entanglement and quantum computation with ions in thermal motion. Phys. Rev. A 62, 022311 (2000)

    ADS  Article  Google Scholar 

  11. 11

    Milburn, G. J. Schneider, S. & James, D. F. V. Ion trap quantum computing with warm ions. Fortschr. Phys. 48, 801–810 (2000)

    CAS  Article  Google Scholar 

  12. 12

    Wunderlich, C. in Laser Physics at the Limit (eds Meschede, D., Zimmermann, C. & Figger, H. ) 261–271 (Springer, 2002)

    Google Scholar 

  13. 13

    Wunderlich, C. & Balzer, C. Quantum measurements and new concepts for experiments with trapped ions. Adv. At. Mol. Phys. 49, 293–372 (2003)

    ADS  CAS  Article  Google Scholar 

  14. 14

    Mc Hugh, D. & Twamley, J. Quantum computer using a trapped-ion spin molecule and microwave radiation. Phys. Rev. A 71, 012315 (2005)

    ADS  Article  Google Scholar 

  15. 15

    Wang, S. X. Labaziewicz, J. Ge, Y., Shewmon, R. & Chuang, I. L. Individual addressing of ions using magnetic field gradients in a surface-electrode ion trap. Appl. Phys. Lett. 94, 094103 (2009)

    ADS  Article  Google Scholar 

  16. 16

    Johanning, M. et al. Individual addressing of trapped ions and coupling of motional and spin states using RF radiation. Phys. Rev. Lett. 102, 073004 (2009)

    ADS  CAS  Article  Google Scholar 

  17. 17

    Häffner, H. et al. Robust entanglement. Appl. Phys. B 81, 151–153 (2005)

    ADS  Article  Google Scholar 

  18. 18

    Kielpinski, D. et al. A decoherence-free quantum memory using trapped ions. Science 291, 1013–1015 (2001)

    ADS  CAS  Article  Google Scholar 

  19. 19

    Home, J. P. et al. Complete methods set for scalable ion trap quantum information processing. Science 325, 1227–1230 (2009)

    ADS  MathSciNet  CAS  Article  Google Scholar 

  20. 20

    Viola, L. & Lloyd, S. Dynamical suppression of decoherence in two-state quantum systems. Phys. Rev. A 58, 2733–2744 (1998)

    ADS  MathSciNet  CAS  Article  Google Scholar 

  21. 21

    Rabl, P. et al. Strong magnetic coupling between an electronic spin qubit and a mechanical resonator. Phys. Rev. B 79, 041302 (2009)

    ADS  Article  Google Scholar 

  22. 22

    Biercuk, M. J. et al. Optimized dynamical decoupling in a model quantum memory. Nature 458, 996–1000 (2009)

    ADS  CAS  Article  Google Scholar 

  23. 23

    Bluhm, H. et al. Dephasing time of GaAs electron-spin qubits coupled to a nuclear bath exceeding 200 μs. Nature Phys. 7, 109–113 (2011)

    ADS  CAS  Article  Google Scholar 

  24. 24

    Vitanov, N. V. Fleischhauer, M. Shore, B. W. & Bergmann, K. Coherent manipulation of atoms and molecules by sequential laser pulses. Adv. At. Mol. Phys. 46, 55–190 (2001)

    ADS  CAS  Article  Google Scholar 

  25. 25

    Sørensen, J. et al. Efficient coherent internal state transfer in trapped ions using stimulated Raman adiabatic passage. New J. Phys. 8, 261 1–11. (2006)

    MathSciNet  Article  Google Scholar 

  26. 26

    Cirac, J. I. & Zoller, P. Quantum computations with cold trapped ions. Phys. Rev. Lett. 74, 4091–4094 (1995)

    ADS  CAS  Article  Google Scholar 

  27. 27

    Specht, H. P. et al. A single-atom quantum memory. Nature 473, 190–192 (2011)

    ADS  CAS  Article  Google Scholar 

  28. 28

    Simon, C. et al. Quantum memories. Eur. Phys. J. D 58, 1–22 (2010)

    ADS  CAS  Article  Google Scholar 

  29. 29

    Clarke, J. & Wilhelm, F. K. Superconducting quantum bits. Nature 453, 1031–1042 (2008)

    ADS  CAS  Article  Google Scholar 

  30. 30

    Hannemann, T. et al. Self-learning estimation of quantum states. Phys. Rev. A 65, 050303 1–4. (2002)

    Article  Google Scholar 

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Acknowledgements

Technical help with the microwave set-up by T. F. Gloger is acknowledged. We acknowledge support by the Bundesministerium für Bildung und Forschung (FK 01BQ1012 and P3352014), the Deutsche Forschungsgemeinschaft, the European Commission under the STREP PICC, the German-Israeli Foundation, secunet AG and the Alexander von Humboldt Foundation.

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N.T., I.B., M.J., A.F.V. and Ch.W. contributed to the experiment, the analysis of experimental and theoretical results, and the writing of the manuscript. A.R. and M.B.P. contributed to the theory, the analysis of theoretical and experimental results, and the writing of the manuscript. A.R. and Ch.W. had the idea for theory and experiment.

Corresponding authors

Correspondence to A. Retzker or Ch. Wunderlich.

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The authors declare no competing financial interests.

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Timoney, N., Baumgart, I., Johanning, M. et al. Quantum gates and memory using microwave-dressed states. Nature 476, 185–188 (2011). https://doi.org/10.1038/nature10319

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