Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Coherent quantum state storage and transfer between two phase qubits via a resonant cavity

Nature volume 449, pages 438–442 (2007)Cite this article

Abstract

As with classical information processing, a quantum information processor requires bits (qubits) that can be independently addressed and read out, long-term memory elements to store arbitrary quantum states1,2, and the ability to transfer quantum information through a coherent communication bus accessible to a large number of qubits3,4. Superconducting qubits made with scalable microfabrication techniques are a promising candidate for the realization of a large-scale quantum information processor5,6,7,8,9. Although these systems have successfully passed tests of coherent coupling for up to four qubits10,11,12,13, communication of individual quantum states between superconducting qubits via a quantum bus has not yet been realized. Here, we perform an experiment demonstrating the ability to coherently transfer quantum states between two superconducting Josephson phase qubits through a quantum bus. This quantum bus is a resonant cavity formed by an open-ended superconducting transmission line of length 7 mm. After preparing an initial quantum state with the first qubit, this quantum information is transferred and stored as a nonclassical photon state of the resonant cavity, then retrieved later by the second qubit connected to the opposite end of the cavity. Beyond simple state transfer, these results suggest that a high-quality-factor superconducting cavity could also function as a useful short-term memory element. The basic architecture presented here can be expanded, offering the possibility for the coherent interaction of a large number of superconducting qubits.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Schematic description of the experiment set-up.
Figure 2: Demonstration of strongly coupled circuit QED.
Figure 3: Experimental data showing the quantum state transfer from qubit A to qubit B via the cavity.
Figure 4: Demonstration of the coherent transfer of a quantum state through the quantum bus.

Similar content being viewed by others

References

  1. Julsgaard, B., Sherson, J., Cirac, J. I., Fiurek, J. & Polzik, E. S. Experimental demonstration of quantum memory for light. Nature 432, 482–486 (2004)

    Article  ADS  CAS  Google Scholar 

  2. Langer, C. et al. Long-lived qubit memory using atomic ions. Phys. Rev. Lett. 95, 060502 (2005)

    Article  ADS  CAS  Google Scholar 

  3. Plastina, F. & Falci, G. Communicating Josephson qubits. Phys. Rev. B 67, 224514 (2003)

    Article  ADS  Google Scholar 

  4. Cleland, A. N. & Geller, M. R. Superconducting qubit storage and entanglement with nano-mechanical resonators. Phys. Rev. Lett. 93, 070501 (2004)

    Article  ADS  CAS  Google Scholar 

  5. Bouchiat, V. et al. Quantum coherence with a single Cooper pair. Phys. Scr. T76, 165–170 (1998)

    Article  ADS  CAS  Google Scholar 

  6. Nakamura, Y., Pashkin, Yu. A. & Tsai, J. S. Coherent control of macroscopic quantum states in a single-Cooper-pair box. Nature 398, 786–788 (1999)

    Article  ADS  CAS  Google Scholar 

  7. Vion, D. et al. Manipulating the quantum state of an electrical circuit. Science 296, 886–889 (2002)

    Article  ADS  CAS  Google Scholar 

  8. Chiorescu, I., Nakamura, Y., Harmans, C. J. & Mooij, J. E. Coherent quantum dynamics of a superconducting flux qubit. Science 299, 1869–1871 (2003)

    Article  ADS  CAS  Google Scholar 

  9. Makhlin, Y., Schön, G. & Shnirman, A. Quantum-state engineering with Josephson-junction devices. Rev. Mod. Phys. 73, 357–400 (2001)

    Article  ADS  Google Scholar 

  10. Yamamoto, T., Pashkin, Y. A., Astafiev, O., Nakamura, Y. & Tsai, J. S. Quantum oscillations in two coupled charge qubits. Nature 425, 941–944 (2003)

    Article  ADS  CAS  Google Scholar 

  11. McDermott, R. et al. Simultaneous state measurement of coupled Josephson phase qubits. Science 307, 1299–1302 (2005)

    Article  ADS  CAS  Google Scholar 

  12. Steffen, M. et al. Measurement of the entanglement of two superconducting qubits via state tomography. Science 313, 1423–1425 (2006)

    Article  ADS  MathSciNet  CAS  Google Scholar 

  13. Grajcar, M. et al. Four-qubit device with mixed couplings. Phys. Rev. Lett. 96, 047006 (2006)

    Article  ADS  CAS  Google Scholar 

  14. Schleich, W. P. & Walther, H. Elements of Quantum Information 1st edn, Ch. 1 (Wiley-VCH, New York, 2007)

    Book  Google Scholar 

  15. Haroche, S. & Raimond, J.-M. Exploring the Quantum: Atoms, Cavities, and Photons 1st edn, Ch. 5 (Oxford Univ. Press, Oxford, 2006)

    Book  Google Scholar 

  16. Maître, X. et al. Quantum memory with a single photon in a cavity. Phys. Rev. Lett. 79, 769–772 (1997)

    Article  ADS  Google Scholar 

  17. Buisson, O. & Hekking, F. W. J. in Macroscopic Quantum Coherence and Quantum Computing (eds Averin, D. V., Ruggiero, B. & Silvestrini, P.) 137–145 (Kluwer Academic, New York, 2001)

    Book  Google Scholar 

  18. Blais, A., Huang, R.-S., Wallraff, A., Girvin, S. M. & Schoelkopf, R. J. Cavity quantum electrodynamics for superconducting electrical circuits: An architecture for quantum computation. Phys. Rev. A 69, 062320 (2004)

    Article  ADS  Google Scholar 

  19. Wallraff, A. et al. Strong coupling of a single photon to a superconducting qubit using circuit quantum electrodynamics. Nature 431, 162–167 (2004)

    Article  ADS  CAS  Google Scholar 

  20. Chiorescu, I. et al. Coherent dynamics of a flux qubit coupled to a harmonic oscillator. Nature 431, 159–162 (2004)

    Article  ADS  CAS  Google Scholar 

  21. Johansson, J. et al. Vacuum Rabi oscillations in a macroscopic superconducting qubit LC oscillator system. Phys. Rev. Lett. 96, 127006 (2006)

    Article  ADS  CAS  Google Scholar 

  22. Koch, R. H. et al. Experimental demonstration of an oscillator stabilized Josephson flux qubit. Phys. Rev. Lett. 96, 127001 (2006)

    Article  ADS  CAS  Google Scholar 

  23. Xu, H. et al. Spectroscopy of three-particle entanglement in a macroscopic superconducting circuit. Phys. Rev. Lett. 94, 027003 (2005)

    Article  ADS  Google Scholar 

  24. Simmonds, R. W. et al. Decoherence in Josephson phase qubits from junction resonators. Phys. Rev. Lett. 93, 077003 (2004)

    Article  ADS  CAS  Google Scholar 

  25. Martinis, J. M., Nam, S., Aumentado, J. & Urbina, C. Rabi oscillations in a large Josephson-junction qubit. Phys. Rev. Lett. 89, 117901 (2002)

    Article  ADS  Google Scholar 

  26. Cooper, K. B. et al. Observation of quantum oscillations between a Josephson phase qubit and a microscopic resonator using fast readout. Phys. Rev. Lett. 93, 180401 (2004)

    Article  ADS  CAS  Google Scholar 

  27. Brune, M. et al. Quantum Rabi oscillation: A direct test of field quantization in a cavity. Phys. Rev. Lett. 76, 1800–1803 (1996)

    Article  ADS  CAS  Google Scholar 

  28. Martinis, J. M. et al. Decoherence in Josephson qubits from dielectric loss. Phys. Rev. Lett. 95, 210503 (2005)

    Article  ADS  Google Scholar 

  29. Day, P. K., LeDuc, H. G., Mazin, B. A., Vayonakis, A. & Zmuidzinas, J. A broadband superconducting detector suitable for use in large arrays. Nature 425, 817–821 (2003)

    Article  ADS  CAS  Google Scholar 

  30. Steffen, M. et al. State tomography of capacitively shunted phase qubits with high fidelity. Phys. Rev. Lett. 97, 050502 (2006)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

We gratefully acknowledge discussions with J. Aumentado, K. Cicak, K. Osborne, R. Schoelkopf and D. Wineland. This work was financially supported by the NIST and the DTO.

Author information

Authors and Affiliations

  1. National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA,

    Mika A. Sillanpää, Jae I. Park & Raymond W. Simmonds

Authors
  1. Mika A. Sillanpää
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Jae I. Park
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Raymond W. Simmonds
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Raymond W. Simmonds.

Ethics declarations

Competing interests

Reprints and permissions information is available at www.nature.com/reprints. The authors declare no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Sillanpää, M., Park, J. & Simmonds, R. Coherent quantum state storage and transfer between two phase qubits via a resonant cavity. Nature 449, 438–442 (2007). https://doi.org/10.1038/nature06124

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature06124

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing