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Accurately computing the electronic properties of a quantum ring

Abstract

A promising approach to study condensed-matter systems is to simulate them on an engineered quantum platform1,2,3,4. However, the accuracy needed to outperform classical methods has not been achieved so far. Here, using 18 superconducting qubits, we provide an experimental blueprint for an accurate condensed-matter simulator and demonstrate how to investigate fundamental electronic properties. We benchmark the underlying method by reconstructing the single-particle band structure of a one-dimensional wire. We demonstrate nearly complete mitigation of decoherence and readout errors, and measure the energy eigenvalues of this wire with an error of approximately 0.01 rad, whereas typical energy scales are of the order of 1 rad. Insight into the fidelity of this algorithm is gained by highlighting the robust properties of a Fourier transform, including the ability to resolve eigenenergies with a statistical uncertainty of 10−4 rad. We also synthesize magnetic flux and disordered local potentials, which are two key tenets of a condensed-matter system. When sweeping the magnetic flux we observe avoided level crossings in the spectrum, providing a detailed fingerprint of the spatial distribution of local disorder. By combining these methods we reconstruct electronic properties of the eigenstates, observing persistent currents and a strong suppression of conductance with added disorder. Our work describes an accurate method for quantum simulation5,6 and paves the way to study new quantum materials with superconducting qubits.

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Fig. 1: Engineering a one-dimensional system with energy, momentum and flux.
Fig. 2: Measuring the single-particle band structure.
Fig. 3: Synthetic flux as a probe of local disorder.
Fig. 4: Inferring current and conductance from avoided level crossings.

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Data availability

The data presented in this study can be found in the Dryad repository located at https://doi.org/10.5061/dryad.4f4qrfj9x.

Code availability

The Python code for processing the data presented in this study can be found in the Dryad repository located at https://doi.org/10.5061/dryad.4f4qrfj9x.

References

  1. Feynman, R. P. Simulating physics with computers. Int. J. Theor. Phys. 21, 467–488 (1982).

    Article  MathSciNet  Google Scholar 

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

    Article  CAS  ADS  Google Scholar 

  3. Bloch, I., Dalibard, J. & Zwerger, W. Many-body physics with ultracold gases. Rev. Mod. Phys. 80, 885 (2008).

    Article  CAS  ADS  Google Scholar 

  4. Georgescu, I., Ashhab, S. & Nori, F. Quantum simulation. Rev. Mod. Phys. 86, 153 (2014).

    Article  ADS  Google Scholar 

  5. Polkovnikov, A., Sengupta, K., Silva, A. & Vengalatorre, M. Nonequilibrium dynamics of closed interacting quantum systems. Rev. Mod. Phys., 83, 863 (2011).

    Article  ADS  Google Scholar 

  6. Carusotto, I. et al. Photonic materials in circuit quantum electrodynamics. Nat. Phys. 16, 268–279 (2020).

    Article  CAS  Google Scholar 

  7. Qin, M. et al. Absence of superconductivity in the pure two-dimensional Hubbard model. Phys. Rev. X 10, 031016 (2020).

    CAS  Google Scholar 

  8. Jiang, H. C. & Devereaux, T. P. Superconductivity in the doped Hubbard model and its interplay with next-nearest hopping t'. Science 365, 1424–1428 (2019).

    Article  MathSciNet  CAS  ADS  Google Scholar 

  9. Willett, R. et al. Observation of an even-denominator quantum number in the fractional quantum Hall effect. Phys. Rev. Lett. 59, 1776–1779 (1987).

    Article  CAS  ADS  Google Scholar 

  10. Dolev, M., Heiblum, M., Umansky, V., Stern, A. & Mahalu, D. Observation of a quarter of an electron charge at the v = 5/2 quantum Hall state. Nature 452, 829–834 (2008).

    Article  CAS  ADS  Google Scholar 

  11. Willett, R. et al. Interference measurements of non-abelian e/4 & abelian e/2 quasiparticle braiding. Preprint at https://arxiv.org/abs/1905.10248 (2019).

  12. Chen, Y. et al. Qubit architecture with high coherence and fast tunable coupling. Phys. Rev. Lett. 113, 220502 (2014).

    Article  ADS  Google Scholar 

  13. Neill, C. A Path Towards Quantum Supremacy with Superconducting Qubits. PhD Thesis, Univ. California, Santa Barbara (2017).

  14. Arute, F. et al. Quantum supremacy using a programmable superconducting processor. Nature 574, 505–510 (2019).

    Article  CAS  ADS  Google Scholar 

  15. Giamarchi, T. Quantum Physics in One Dimension Vol. 121 (Clarendon, 2003).

  16. Jotzu, G. et al. Experimental realization of the topological Haldane model with ultracold fermions. Nature 515, 237–240 (2014).

    Article  CAS  ADS  Google Scholar 

  17. Manovitz, T., Shapira, Y., Akerman, N., Stern, A. & Ozeri, R. Quantum simulations with complex geometries and synthetic gauge fields in a trapped ion chain. PRX Quantum 1, 020303 (2020).

    Article  Google Scholar 

  18. Roushan, P. et al. Spectroscopic signatures of localization with interacting photons in superconducting qubits. Science 358, 1175–1179 (2017).

    Article  MathSciNet  CAS  ADS  Google Scholar 

  19. Aharonov, Y. & Bohm, D. Significance of electromagnetic potentials in the quantum theory. Phys. Rev. 115, 485–491 (1959).

    Article  MathSciNet  ADS  Google Scholar 

  20. Pal, A. & Huse, D. Many-body localization phase transition. Phys. Rev. B 82, 174411 (2010).

    Article  ADS  Google Scholar 

  21. Ponte, P., Papić, Z., Huveneers, F. & Abanin, D. A. Many-body localization in periodically driven systems. Phys. Rev. Lett. 114, 140401 (2015).

    Article  ADS  Google Scholar 

  22. Schreiber, M. et al. Observation of many-body localization of interacting fermions in a quasirandom optical lattice. Science 349, 842–845 (2015).

    Article  MathSciNet  CAS  ADS  Google Scholar 

  23. Kleemans, N. A. et al. Oscillatory persistent currents in self-assembled quantum rings. Phys. Rev. Lett. 99, 146808 (2007).

    Article  CAS  ADS  Google Scholar 

  24. Bleszynski-Jayich, A. C. et al. Persistent currents in normal metal rings. Science 326, 272–275 (2009).

    Article  CAS  ADS  Google Scholar 

  25. Thouless, D., Kohmoto, M., Nightingale, M. & den Nijs, M. Quantized Hall conductance in a two-dimensional periodic potential. Phys. Rev. Lett. 49, 405–408 (1982).

    Article  CAS  ADS  Google Scholar 

  26. Braun, D., Hofstetter, E., MacKinnon, A. & Montambaux, G. Level curvatures and conductances: A numerical study of the thouless relation. Phys. Rev. B 55, 7557 (1997).

    Article  CAS  ADS  Google Scholar 

  27. White, S. R. Density matrix formulation for quantum renormalization groups. Phys. Rev. Lett. 69, 2863–2866 (1992).

    Article  CAS  ADS  Google Scholar 

  28. White, S. R. & Huse, D. A. Numerical renormalization-group study of low-lying eigenstates of the antiferromagnetic S = 1 Heisenberg chain. Phys. Rev. B 48, 3844–3852 (1993).

    Article  CAS  ADS  Google Scholar 

  29. Kelly, J., O’Malley, P., Neeley, M., Neven, H. & Martinis, J. Physical qubit calibration on a directed acyclic graph. Preprint at https://arxiv.org/abs/1803.03226 (2018).

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Acknowledgements

We acknowledge discussions with B. Altshuler and L. Faoro. We thank J. Platt, J. Dean and J. Yagnik for their executive sponsorship of the Google Quantum AI team, and for their continued engagement and support. We thank A. Brown and J. Platt for reviewing and providing advice on the draft of the manuscript.

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Authors and Affiliations

Authors

Contributions

C.N. designed and executed the experiment. C.N. and P.R. wrote the manuscript. C.N., T.M. and V. Smelyanskiy wrote the Supplementary Information. V. Smelyanskiy, S.B., T.M., Z.J., X.M., L.B.I. and C.N. provided the theoretical support and analysis techniques, the theory of Floquet calibration and the open system model. Y.C., V. Smelyanskiy and H.N. led and coordinated the project. Infrastructure support was provided by the hardware team. All authors contributed to revising the manuscript and the Supplementary Information.

Corresponding authors

Correspondence to P. Roushan, Y. Chen or V. Smelyanskiy.

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The authors declare no competing interests.

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Peer review information Nature thanks Jonas Bylander, Frank Wilhelm and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

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Supplementary Information

This file contains Supplementary Sections A-G, including Supplementary Figures 1-15 – see contents page for details.

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Neill, C., McCourt, T., Mi, X. et al. Accurately computing the electronic properties of a quantum ring. Nature 594, 508–512 (2021). https://doi.org/10.1038/s41586-021-03576-2

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