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Ideal refocusing of an optically active spin qubit under strong hyperfine interactions

Nature Nanotechnology volume 18, pages 257–263 (2023)Cite this article

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Abstract

Combining highly coherent spin control with efficient light-matter coupling offers great opportunities for quantum communication and computing. Optically active semiconductor quantum dots have unparalleled photonic properties but also modest spin coherence limited by their resident nuclei. The nuclear inhomogeneity has thus far bound all dynamical decoupling measurements to a few microseconds. Here, we eliminate this inhomogeneity using lattice-matched GaAs–AlGaAs quantum dot devices and demonstrate dynamical decoupling of the electron spin qubit beyond 0.113(3) ms. Leveraging the 99.30(5)% visibility of our optical π-pulse gates, we use up to Nπ = 81 decoupling pulses and find a coherence time scaling of \({N}_{\uppi }^{0.75(2)}\). This scaling manifests an ideal refocusing of strong interactions between the electron and the nuclear spin ensemble, free of extrinsic noise, which holds the promise of lifetime-limited spin coherence. Our findings demonstrate that the most punishing material science challenge for such quantum dot devices has a remedy and constitute the basis for highly coherent spin–photon interfaces.

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Fig. 1: Optically addressable spin in a GaAs–AlGaAs QD.
Fig. 2: Complete qubit control.
Fig. 3: Electron spin coherence.
Fig. 4: Key parameters for device performance.

Data availability

The data that support the findings of this study are available from the corresponding authors upon request.

Code availability

The code that models the decoherence of the dynamically decoupled electron spin is available at https://github.com/CoherentQD/CPMG_simulation.

References

  1. Nickerson, N. H., Fitzsimons, J. F. & Benjamin, S. C. Freely scalable quantum technologies using cells of 5-to-50 qubits with very lossy and noisy photonic links. Phys. Rev. X 4, 041041 (2014).

    Google Scholar 

  2. Monroe, C. et al. Large-scale modular quantum-computer architecture with atomic memory and photonic interconnects. Phys. Rev. A 89, 022317 (2014).

    Google Scholar 

  3. Cohen, L. Z., Kim, I. H., Bartlett, S. D. & Brown, B. J. Low-overhead fault-tolerant quantum computing using long-range connectivity. Sci. Adv. 8, eabn1717 (2022).

    Google Scholar 

  4. Gimeno-Segovia, M., Shadbolt, P., Browne, D. E. & Rudolph, T. From three-photon Greenberger-Horne-Zeilinger states to ballistic universal quantum computation. Phys. Rev. Lett. 115, 020502 (2015).

    Google Scholar 

  5. Stephenson, L. J. et al. High-rate, high-fidelity entanglement of qubits across an elementary quantum network. Phys. Rev. Lett. 124, 110501 (2020).

    CAS  Google Scholar 

  6. Postler, L. et al. Demonstration of fault-tolerant universal quantum gate operations. Nature 605, 675–680 (2022).

    CAS  Google Scholar 

  7. Abobeih, M. H. et al. Fault-tolerant operation of a logical qubit in a diamond quantum processor. Nature 606, 884–889 (2022).

    CAS  Google Scholar 

  8. Bergeron, L. et al. Silicon-integrated telecommunications photon-spin interface. PRX Quantum 1, 020301 (2020).

    Google Scholar 

  9. Christle, D. J. et al. Isolated spin qubits in SiC with a high-fidelity infrared spin-to-photon interface. Phys. Rev. X 7, 021046 (2017).

    Google Scholar 

  10. Ruskuc, A., Wu, C.-J., Rochman, J., Choi, J. & Faraon, A. Nuclear spin-wave quantum register for a solid-state qubit. Nature 602, 408–413 (2022).

    CAS  Google Scholar 

  11. Raha, M. et al. Optical quantum nondemolition measurement of a single rare earth ion qubit. Nat. Commun. 11, 1605 (2020).

    CAS  Google Scholar 

  12. Berezovsky, J., Mikkelsen, M. H., Stoltz, N. G., Coldren, L. A. & Awschalom, D. D. Picosecond coherent optical manipulation of a single electron spin in a quantum dot. Science 320, 349–352 (2008).

    CAS  Google Scholar 

  13. De Greve, K. et al. Ultrafast coherent control and suppressed nuclear feedback of a single quantum dot hole qubit. Nat. Phys. 7, 872–878 (2011).

    Google Scholar 

  14. Godden, T. M. et al. Coherent optical control of the spin of a single hole in an InAs/GaAs quantum dot. Phys. Rev. Lett. 108, 017402 (2012).

    CAS  Google Scholar 

  15. Pfaff, W. et al. Unconditional quantum teleportation between distant solid-state quantum bits. Science 345, 532–535 (2014).

    CAS  Google Scholar 

  16. Pompili, M. et al. Realization of a multinode quantum network of remote solid-state qubits. Science 372, 259–264 (2021).

    CAS  Google Scholar 

  17. Schwartz, I. et al. Deterministic generation of a cluster state of entangled photons. Science 354, 434–437 (2016).

    CAS  Google Scholar 

  18. Istrati, D. et al. Sequential generation of linear cluster states from a single photon emitter. Nat. Commun. 11, 5501 (2020).

    CAS  Google Scholar 

  19. Wang, H. et al. Towards optimal single-photon sources from polarized microcavities. Nat. Photon. 13, 770–775 (2019).

    CAS  Google Scholar 

  20. Liu, J. et al. A solid-state source of strongly entangled photon pairs with high brightness and indistinguishability. Nat. Nanotechnol. 14, 586–593 (2019).

    CAS  Google Scholar 

  21. Tomm, N. et al. A bright and fast source of coherent single photons. Nat. Nanotechnol. 16, 399–403 (2021).

    CAS  Google Scholar 

  22. Appel, M. H. et al. Coherent spin-photon interface with waveguide induced cycling transitions. Phys. Rev. Lett. 126, 013602 (2021).

    CAS  Google Scholar 

  23. Thomas, S. E. et al. Bright polarized single-photon source based on a linear dipole. Phys. Rev. Lett. 126, 233601 (2021).

    CAS  Google Scholar 

  24. Varnava, M., Browne, D. E. & Rudolph, T. How good must single photon sources and detectors be for efficient linear optical quantum computation? Phys. Rev. Lett. 100, 060502 (2008).

    Google Scholar 

  25. Pant, M., Towsley, D., Englund, D. & Guha, S. Percolation thresholds for photonic quantum computing. Nat. Commun. 10, 1070 (2019).

    Google Scholar 

  26. Press, D., Ladd, T. D., Zhang, B. & Yamamoto, Y. Complete quantum control of a single quantum dot spin using ultrafast optical pulses. Nature 456, 218–221 (2008).

    CAS  Google Scholar 

  27. De Greve, K. et al. Quantum-dot spin–photon entanglement via frequency downconversion to telecom wavelength. Nature 491, 421–425 (2012).

    Google Scholar 

  28. Appel, M. H. et al. Entangling a hole spin with a time-bin photon: a waveguide approach for quantum dot sources of multiphoton entanglement. Phys. Rev. Lett. 128, 233602 (2022).

    CAS  Google Scholar 

  29. Delteil, A. et al. Generation of heralded entanglement between distant hole spins. Nat. Phys. 12, 218–223 (2016).

    CAS  Google Scholar 

  30. Stockill, R. et al. Phase-tuned entangled state generation between distant spin qubits. Phys. Rev. Lett. 119, 010503 (2017).

    CAS  Google Scholar 

  31. Gangloff, D. A. et al. Quantum interface of an electron and a nuclear ensemble. Science 364, 62–66 (2019).

    CAS  Google Scholar 

  32. Taylor, J. M., Marcus, C. M. & Lukin, M. D. Long-lived memory for mesoscopic quantum bits. Phys. Rev. Lett. 90, 206803 (2003).

    CAS  Google Scholar 

  33. Denning, E. V., Gangloff, D. A., Atatüre, M., Mørk, J. & Le Gall, C. Collective quantum memory activated by a driven central spin. Phys. Rev. Lett. 123, 140502 (2019).

    CAS  Google Scholar 

  34. Stockill, R. et al. Quantum dot spin coherence governed by a strained nuclear environment. Nat. Commun. 7, 12745 (2016).

    CAS  Google Scholar 

  35. Gong, Q., Offermans, P., Nötzel, R., Koenraad, P. M. & Wolter, J. H. Capping process of InAs/GaAs quantum dots studied by cross-sectional scanning tunneling microscopy. Appl. Phys. Lett. 85, 5697 (2004).

    CAS  Google Scholar 

  36. Bechtold, A. et al. Three-stage decoherence dynamics of an electron spin qubit in an optically active quantum dot. Nat. Phys. 11, 1005–1008 (2015).

    CAS  Google Scholar 

  37. Covre da Silva, S. F. et al. GaAs quantum dots grown by droplet etching epitaxy as quantum light sources. Appl. Phys. Lett. 119, 120502 (2021).

    Google Scholar 

  38. Schöll, E. et al. Resonance fluorescence of GaAs quantum dots with near-unity photon indistinguishability. Nano Lett. 19, 2404–2410 (2019).

    Google Scholar 

  39. Zhai, L. et al. Low-noise GaAs quantum dots for quantum photonics. Nat. Commun. 11, 4745 (2020).

    CAS  Google Scholar 

  40. Chekhovich, E. A., Covre da Silva, S. F. & Rastelli, A. Nuclear spin quantum register in an optically active semiconductor quantum dot. Nat. Nanotechnol. 15, 999–1004 (2020).

    CAS  Google Scholar 

  41. Schimpf, C., Manna, S., Covre da Silva, S. F., Aigner, M. & Rastelli, A. Entanglement-based quantum key distribution with a blinking-free quantum dot operated at a temperature up to 20 K. Adv. Photon. 3, 065001 (2021).

    CAS  Google Scholar 

  42. Kuhlmann, A. V. et al. Charge noise and spin noise in a semiconductor quantum device. Nat. Phys. 9, 570–575 (2013).

    CAS  Google Scholar 

  43. Gillard, G. et al. Fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot. npj Quantum Inf. 7, 43 (2021).

    Google Scholar 

  44. Bodey, J. H. et al. Optical spin locking of a solid-state qubit. npj Quantum Inf. 5, 95 (2019).

    Google Scholar 

  45. Cywiński, Ł., Witzel, W. M. & Das Sarma, S. Pure quantum dephasing of a solid-state electron spin qubit in a large nuclear spin bath coupled by long-range hyperfine-mediated interactions. Phys. Rev. B 79, 245314 (2009).

    Google Scholar 

  46. Botzem, T. et al. Quadrupolar and anisotropy effects on dephasing in two-electron spin qubits in GaAs. Nat. Commun. 7, 11170 (2016).

    CAS  Google Scholar 

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

    CAS  Google Scholar 

  48. Malinowski, F. K. et al. Notch filtering the nuclear environment of a spin qubit. Nat. Nanotechnol. 12, 16–20 (2016).

    Google Scholar 

  49. Malinowski, F. K. et al. Spectrum of the nuclear environment for GaAs spin qubits. Phys. Rev. Lett. 118, 177702 (2017).

    Google Scholar 

  50. de Lange, G., Wang, Z. H., Ristè, D., Dobrovitski, V. V. & Hanson, R. Universal dynamical decoupling of a single solid-state spin from a spin bath. Science 330, 60–63 (2010).

    Google Scholar 

  51. Huthmacher, L. et al. Coherence of a dynamically decoupled quantum-dot hole spin. Phys. Rev. B 97, 241413 (2018).

    CAS  Google Scholar 

  52. Ragunathan, G. Nuclear Spin Phenomena in III-V and II-VI Semiconductor Quantum Dots. PhD thesis, University of Sheffield (2019).

  53. Ulhaq, A. et al. Vanishing electron g factor and long-lived nuclear spin polarization in weakly strained nanohole-filled GaAs/AlGaAs quantum dots. Phys. Rev. B 93, 165306 (2016).

    Google Scholar 

  54. Chekhovich, E. A., Hopkinson, M., Skolnick, M. S. & Tartakovskii, A. I. Suppression of nuclear spin bath fluctuations in self-assembled quantum dots induced by inhomogeneous strain. Nat. Commun. 6, 6348 (2015).

    CAS  Google Scholar 

  55. Knijn, P. J. et al. A solid-state NMR and DFT study of compositional modulations in AlxGa1−xAs. Phys. Chem. Chem. Phys. 12, 11517–11535 (2010).

    CAS  Google Scholar 

  56. Chekhovich, E. A. et al. Measurement of the spin temperature of optically cooled nuclei and GaAs hyperfine constants in GaAs/AlGaAs quantum dots. Nat. Mater. 16, 982–986 (2017).

    CAS  Google Scholar 

  57. van Bree, J. et al. Anisotropy of electron and hole g tensors of quantum dots: an intuitive picture based on spin-correlated orbital currents. Phys. Rev. B 93, 035311 (2016).

    Google Scholar 

  58. Wolters, J. et al. Simple atomic quantum memory suitable for semiconductor quantum dot single photons. Phys. Rev. Lett. 119, 060502 (2017).

    Google Scholar 

  59. Heyn, C. et al. Highly uniform and strain-free GaAs quantum dots fabricated by filling of self-assembled nanoholes. Appl. Phys. Lett. 94, 183113 (2009).

    Google Scholar 

  60. Atkinson, P., Zallo, E. & Schmidt, O. G. Independent wavelength and density control of uniform GaAs/AlGaAs quantum dots grown by infilling self-assembled nanoholes. J. Appl. Phys. 112, 054303 (2012).

    Google Scholar 

  61. Huo, Y. H., Rastelli, A. & Schmidt, O. G. Ultra-small excitonic fine structure splitting in highly symmetric quantum dots on GaAs (001) substrate. Appl. Phys. Lett. 102, 152105 (2013).

    Google Scholar 

  62. Houel, J. et al. Probing single-charge fluctuations at a GaAs/AlAs interface using laser spectroscopy on a nearby InGaAs quantum dot. Phys. Rev. Lett. 108, 107401 (2012).

    CAS  Google Scholar 

  63. Virtanen, P. et al. SciPy 1.0: fundamental algorithms for scientific computing in Python. Nat. Methods 17, 261–272 (2020).

    CAS  Google Scholar 

  64. Chekhovich, E. A. et al. Cross calibration of deformation potentials and gradient-elastic tensors of GaAs using photoluminescence and nuclear magnetic resonance spectroscopy in GaAs/AlGaAs quantum dot structures. Phys. Rev. B 97, 235311 (2018).

    CAS  Google Scholar 

  65. Neder, I. et al. Semiclassical model for the dephasing of a two-electron spin qubit coupled to a coherently evolving nuclear spin bath. Phys. Rev. B 84, 035441 (2011).

    Google Scholar 

Download references

Acknowledgements

We acknowledge support from the Royal Society (EA/181068; C.L.G.), the US Office of Naval Research Global (N62909-19-1-2115; M.A.), the EU Horizon 2020 FET Open project QLUSTER (862035; C.L.G. and M.A.), the EU Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant QUDOT-TECH (861097; M.A.), Qurope (899814; A.R.), ASCENT+ (871130; A. R.), Engineering and Physical Sciences Research Council grant EP/V048333/1 (E.A.C.) and the Austrian Science Fund (FWF; FG 5, P 30459, I 4380, I 4320 and I 3762; A.R.), the LIT Secure and Correct Systems Lab platform is funded by the state of Upper Austria. L.Z., J.H.B. and D.M.J. acknowledge support from the EPSRC DTP. D.A.G. acknowledges a St. John’s College Fellowship and a Royal Society University Research Fellowship; C.LG., a Dorothy Hodgkin Royal Society Fellowship; and E.A.C., a Royal Society University Research Fellowship. We also thank Ł. Cywiński, M. E. Flatté, C. E. Pryor, H. Bluhm, P. Atkinson, A. J. Garcia, G. Undeutsch and P. Klenovský for fruitful discussions.

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Author notes

  1. These authors contributed equally: Noah Shofer, Jonathan H. Bodey, Santanu Manna.

Authors and Affiliations

  1. Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom

    Leon Zaporski, Noah Shofer, Jonathan H. Bodey, Martin Hayhurst Appel, John Jarman, Geoffroy Delamare, Gunhee Park, Urs Haeusler, Dorian A. Gangloff, Mete Atatüre & Claire Le Gall

  2. Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Linz, Austria

    Santanu Manna, Christian Schimpf, Saimon Filipe Covre da Silva & Armando Rastelli

  3. Department of Electrical Engineering, Indian Institute of Technology Delhi, New Delhi, India

    Santanu Manna

  4. Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom

    George Gillard & Evgeny A. Chekhovich

  5. Department of Engineering Science, University of Oxford, Oxford, United Kingdom

    Dorian A. Gangloff

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Contributions

L.Z., D.A.G., M.A. and C.L.G. conceived the spin control experiments; E.A.C. conceived the NMR experiments; and E.A.C. and A.R. conceived the QD device. L.Z., J.H.B., N.S., M.H.A., G.D., G.P. and C.L.G. carried out the spin control and resonance fluorescence experiments; L.Z. and C.L.G. performed the corresponding data analysis, theory and simulations; G.G. and E.A.C. carried out the NMR experiments; S.M. and S.C.d.S. performed the molecular beam epitaxy growth; and C.S. characterized the samples. S.M., J.J. and N.S. processed the QD devices. All authors contributed to the discussion of the analysis and the results. All authors participated in the preparation of the manuscript.

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Correspondence to Leon Zaporski, Mete Atatüre or Claire Le Gall.

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Extended data

Extended Data Fig. 1 QD device.

Schematics of the QD device outlining the composition of the n–i–p heterostructure (Linz Ref. SA0553), the electrical contacts (Methods) and the solid immersion lens (SIL).

Extended Data Fig. 2 Experimental set-up.

AOM = acousto-optic modulator; EOM = electro-optic modulator; APD = avalanche photodiode; AWG = arbitrary waveform generator. Colors of the laser beams correspond to the driven processes (readout, depolarization and spin control) outlined in the energy level diagram on the right.

Extended Data Fig. 3 π-pulse visibility.

a, Visibility measurement on a 40s timescale with Nπ = 162. The left panel displays the readout signal for \(\left\vert \uparrow \right\rangle\) -state initialization. The integrated counts under the yellow dark-shaded area are background-subtracted with the counts in the yellow light-shaded area, yielding cts↑ = 1753. The right panel displays the readout signal following the same pulse sequence with an additional π-pulse (\(\left\vert \downarrow \right\rangle\)-state initialization) yielding cts↓ = 917. This corresponds to a π-pulse visibility of \({{{\mathcal{F}}}}=99.30(5) \%\) (Methods). b, Visibility on long timescales. Data points display the fitted maximal visibility, \({v}_{\max }\), in long CPMG measurements as a function of the number of π-pulses in the sequence, Nπ. The black curve illustrates that a π-pulse visibility \(\bar{{{{\mathcal{F}}}}}=97.81(5) \%\) is typically achieved over longer integration times (Methods). The error bars represent the standard deviation errors on fit parameter \({v}_{\max }\).

Extended Data Fig. 4 NMR datasets.

a, Inverse NMR spectrum of nuclear transition frequencies resolved in an extrinsically strained device (\({\nu }_{Q}^{{{{\rm{ext}}}}}=250\) kHz), displaying a sharp central transition (CT) together with broader satellite transitions (ST). b, Inverse NMR lineshape of the blue-detuned satellite transition together with a skew-normal fit (the red solid curve), given by a function S(A)(ν) from Eq. (8) in Methods, with fitted parameters A = 158(1) μeV × kHz, μ(A) = 252.21(4) kHz, σ(A) = 9.74(8) kHz, ζ(A) = 3.22(8) and C = 0.72(3) μeV, corresponding to a FWHM = 22.9(2) kHz. c, Integral NMR spectrum of the blue-detuned satellite transition. The solid red curve displays the normalized cumulative distribution obtained from the fit to the data in Extended Data Fig. 4b (cf. Eq. (10) in Methods); the mismatch indicates the presence of a broader pedestal (see Fig. 4a), which we fit with a Gaussian distribution centred at μ(B) = 246(2) kHz with FWHM = 172(9) kHz and relative weight β = 0.244(7). The resulting sum fit, given by function CDF(ν) from Eq. (11) in Methods (normalized to 13.09 μeV), is displayed as the turquoise solid curve.

Extended Data Fig. 5 Global fit to the CPMG dataset.

The electronic coherence function from the Eq. (15), that is W⊥(t), was calculated with our model and globally fitted to the CPMG data sub-sets (the black points) with: a, Nπ = 1, b, Nπ = 2, c, Nπ = 3, d, Nπ = 4, e, Nπ = 5, f, Nπ = 8, g, Nπ = 9, h, Nπ = 27 and i, Nπ = 81, all taken at B = 6.5 T. The set of the solid red curves displays the best global fit.

Extended Data Fig. 6 Assessing the goodness of the global fit to the CPMG dataset.

Weighted residual sum of squares per data point, averaged over all the CPMG data subsets of varied Nπ, as a function of two global fit parameters: β and scaling factor κ. Best global fit is found for β = 0.35 and κ = 1.45.

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Supplementary Information

Supplementary Figs. 1–3, Tables 1 and 2 and Discussion.

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Zaporski, L., Shofer, N., Bodey, J.H. et al. Ideal refocusing of an optically active spin qubit under strong hyperfine interactions. Nat. Nanotechnol. 18, 257–263 (2023). https://doi.org/10.1038/s41565-022-01282-2

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