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Coherent coupling and non-destructive measurement of trapped-ion mechanical oscillators

Nature Physics volume 20, pages 1636–1641 (2024)Cite this article

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Abstract

Precise quantum control and measurement of several harmonic oscillators, such as the modes of the electromagnetic field in a cavity or of mechanical motion, are key for their use as quantum platforms. The motional modes of trapped ions can be individually controlled and have good coherence properties. However, achieving high-fidelity two-mode operations and non-destructive measurements of the motional state has been challenging. Here we demonstrate the coherent exchange of single motional quanta between spectrally separated harmonic motional modes of a trapped-ion crystal. The timing, strength, and phase of the coupling are controlled through an oscillating electric potential with suitable spatial variation. Coupling rates that are much larger than decoherence rates enable demonstrations of high-fidelity quantum state transfer and beam-splitter operations, entanglement of motional modes, and Hong–Ou–Mandel-type interference. Additionally, we use the motional coupling to enable repeated non-destructive projective measurement of a trapped-ion motional state. Our work enhances the suitability of trapped-ion motion for continuous-variable quantum computing and error correction and may provide opportunities to improve the performance of motional cooling and motion-mediated entangling interactions.

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Fig. 1: Coupled quantum mechanical oscillators.
Fig. 2: Coherent coupling dynamics.
Fig. 3: Repeated interrogation of a near-ground-state thermal distribution of trapped-ion motion.

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Source data are provided with this paper. All other data that support the plots within this paper are available from the corresponding authors upon reasonable request.

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The simulation and analysis codes are available from the corresponding authors upon reasonable request.

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Acknowledgements

We thank H. Knaack and J. Stuart for helpful comments on the paper. P.-Y.H., J.J.W., S.D.E. and G.Z. acknowledge support from the Professional Research Experience Program operated jointly by the National Institute of Standards and Technology (NIST) and the University of Colorado. S.D.E. acknowledges support from a National Science Foundation Graduate Research Fellowship (Grant No. DGE 1650115). D.C.C. and A.D.B. acknowledge support from a National Research Council postdoctoral fellowship. This work was supported by the Intelligence Advanced Research Projects Activity and the NIST Quantum Information Program.

Author information

Author notes

  1. Pan-Yu Hou

    Present address: Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, People’s Republic of China

  2. Stephen D. Erickson

    Present address: Quantinuum, Broomfield, CO, USA

  3. Daniel C. Cole

    Present address: ColdQuanta Inc, Boulder, CO, USA

  4. Giorgio Zarantonello

    Present address: QUDORA Technologies GmbH, Braunschweig, Germany

  5. Giorgio Zarantonello

    Present address: Institute of Quantum Optics, Leibniz University Hannover, Hannover, Germany

Authors and Affiliations

  1. National Institute of Standards and Technology, Boulder, CO, USA

    Pan-Yu Hou, Jenny J. Wu, Stephen D. Erickson, Daniel C. Cole, Giorgio Zarantonello, Adam D. Brandt, Shawn Geller, Alex Kwiatkowski, Scott Glancy, Emanuel Knill, Andrew C. Wilson, Daniel H. Slichter & Dietrich Leibfried

  2. Department of Physics, University of Colorado, Boulder, CO, USA

    Pan-Yu Hou, Jenny J. Wu, Stephen D. Erickson, Giorgio Zarantonello, Shawn Geller & Alex Kwiatkowski

  3. Center for Theory of Quantum Matter, University of Colorado, Boulder, CO, USA

    Emanuel Knill

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Contributions

P.-Y.H. conceived and carried out the experiments, analysed the data and performed the numerical simulations. All authors provided input on the experimental design and data analysis. P.-Y.H., J.J.W., S.D.E., D.C.C., G.Z., A.D.B. and A.C.W. maintained the experimental apparatus. P.-Y.H. and D.L. wrote the paper with input from all authors. D.L., A.C.W. and D.H.S. secured funding for the work. D.L. supervised the work with support from D.H.S.

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Correspondence to Pan-Yu Hou or Dietrich Leibfried.

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Hou, PY., Wu, J.J., Erickson, S.D. et al. Coherent coupling and non-destructive measurement of trapped-ion mechanical oscillators. Nat. Phys. 20, 1636–1641 (2024). https://doi.org/10.1038/s41567-024-02585-y

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