Arute, F. et al. Quantum supremacy using a programmable superconducting processor. Nature 574, 505–510 (2019).
Kim, Y. et al. Evidence for the utility of quantum computing before fault tolerance. Nature 618, 500–505 (2023).
Osman, A. et al. Mitigation of frequency collisions in superconducting quantum processors. Phys. Rev. Res. 5, 043001 (2023).
de Leon, N. P. et al. Materials challenges and opportunities for quantum computing hardware. Science 372, eabb2823 (2021).
Kosen, S. et al. Building blocks of a flip-chip integrated superconducting quantum processor. Quantum Sci. Technol. 7, 035018 (2022).
Bravyi, S. et al. High-threshold and low-overhead fault-tolerant quantum memory. Nature 627, 778–782 (2024).
Acharya, R. et al. Multiplexed superconducting qubit control at millikelvin temperatures with a low-power cryo-CMOS multiplexer. Nat. Electron. 6, 900–909 (2023).
Siddiqi, I. Engineering high-coherence superconducting qubits. Nat. Rev. Mater. 6, 875–891 (2021).
Ding, L. et al. High-fidelity, frequency-flexible two-qubit fluxonium gates with a transmon coupler. Phys. Rev. X 13, 031035 (2023).
Zhao, Y. et al. Realization of an error-correcting surface code with superconducting qubits. Phys. Rev. Lett. 129, 030501 (2022).
Krinner, S. et al. Realizing repeated quantum error correction in a distance-three surface code. Nature 605, 669–674 (2022).
Acharya, R. et al. Suppressing quantum errors by scaling a surface code logical qubit. Nature 614, 676–681 (2023).
Ni, Z. et al. Beating the break-even point with a discrete-variable-encoded logical qubit. Nature https://doi.org/10.1038/s41586-023-05784-4 (2023).
Miao, K. C. et al. Overcoming leakage in quantum error correction. Nat. Phys. https://doi.org/10.1038/s41567-023-02226-w (2023).
Koch, J. et al. Charge insensitive qubit design derived from the Cooper pair box. Phys. Rev. A 76, 042319 (2007).
Wu, Y.-L. et al. Fabrication of Al/AlOx/Al Josephson junctions and superconducting quantum circuits by shadow evaporation and a dynamic oxidation process. Chin. Phys. B 22, 060309 (2013).
Zeng, L., Tran, D. T., Tai, C.-W., Svensson, G. & Olsson, E. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions. Sci. Rep. 6, 29679 (2016).
Cyster, M. J. et al. Simulating the fabrication of aluminium oxide tunnel junctions. npj Quantum Inf. 7, 12 (2021).
Place, A. P. M. et al. New material platform for superconducting transmon qubits with coherence times exceeding 0.3 milliseconds. Nat. Commun. 12, 1779 (2021).
Wang, C. et al. Towards practical quantum computers: transmon qubit with a lifetime approaching 0.5 milliseconds. npj Quantum Inf. 8, 3 (2022).
Kono, S. et al. Mechanically induced correlated errors on superconducting qubits with relaxation times exceeding 0.4 ms. Nat. Commun. 15, 3950 (2024).
Jurcevic, P. et al. Demonstration of quantum volume 64 on a superconducting quantum computing system. Quantum Sci. Technol. 6, 025020 (2021).
Zwerver, A. M. J. et al. Qubits made by advanced semiconductor manufacturing. Nat. Electron. 5, 184–190 (2022).
Neyens, S. et al. Probing single electrons across 300-mm spin qubit wafers. Nature 629, 80–85 (2024).
Zhang, S. et al. Challenges and recent prospectives of 3D heterogeneous integration. e-Prime Adv. Electr. Eng. Electron. Energy 2, 100052 (2022).
Wan, D. et al. Fabrication and room temperature characterization of trilayer junctions for the development of superconducting qubits on 300 mm wafers. Jpn. J. Appl. Phys. 60, SBBI04 (2021).
Kim, S. et al. Enhanced coherence of all-nitride superconducting qubits epitaxially grown on silicon substrate. Commun. Mater. 2, 98 (2021).
Anferov, A., Lee, K.-H., Zhao, F., Simon, J. & Schuster, D. I. Improved coherence in optically defined niobium trilayer-junction qubits. Phys. Rev. Appl. 21, 024047 (2024).
Foroozani, N. et al. Development of transmon qubits solely from optical lithography on 300 mm wafers. Quantum Sci. Technol. 4, 025012 (2019).
Verjauw, J. et al. Path toward manufacturable superconducting qubits with relaxation times exceeding 0.1 ms. npj Quantum Inf. 8, 93 (2022).
Yost, D. R. W. et al. Solid-state qubits integrated with superconducting through-silicon vias. npj Quantum Inf. 6, 59 (2020).
Stehli, A. et al. Coherent superconducting qubits from a subtractive junction fabrication process. Appl. Phys. Lett. 117, 124005 (2020).
Wu, X. et al. Overlap junctions for high coherence superconducting qubits. Appl. Phys. Lett. 111, 032602 (2017).
Van Damme, J. et al. Argon-milling-induced decoherence mechanisms in superconducting quantum circuits. Phys. Rev. Appl. 20, 014034 (2023).
Schlör, S. et al. Correlating decoherence in transmon qubits: low frequency noise by single fluctuators. Phys. Rev. Lett. 123, 190502 (2019).
Burnett, J. J. et al. Decoherence benchmarking of superconducting qubits. npj Quantum Inf. 5, 54 (2019).
Phillips, W. A. Two-level states in glasses. Rep. Prog. Phys. https://doi.org/10.1088/0034-4885/50/12/003 (1987).
Müller, C., Lisenfeld, J., Shnirman, A. & Poletto, S. Interacting two-level defects as sources of fluctuating high-frequency noise in superconducting circuits. Phys. Rev. B 92, 035442 (2015).
Klimov, P. V. et al. Fluctuations of energy-relaxation times in superconducting qubits. Phys. Rev. Lett. 121, 090502 (2018).
Thorbeck, T., Eddins, A., Lauer, I., McClure, D. T. & Carroll, M. Two-level-system dynamics in a superconducting qubit due to background ionizing radiation. PRX Quantum 4, 020356 (2023).
de Graaf, S. E. et al. Two-level systems in superconducting quantum devices due to trapped quasiparticles. Sci. Adv. 6, eabc5055 (2020).
Murray, C. E., Gambetta, J. M., McClure, D. T. & Steffen, M. Analytical determination of participation in superconducting coplanar architectures. IEEE Trans. Microw. Theory Tech. 66, 3724–3733 (2018).
Woods, W. et al. Determining interface dielectric losses in superconducting coplanar-waveguide resonators. Phys. Rev. Appl. 12, 014012 (2019).
Melville, A. et al. Comparison of dielectric loss in titanium nitride and aluminum superconducting resonators. Appl. Phys. Lett. 117, 124004 (2020).
Bal, M. et al. Systematic improvements in transmon qubit coherence enabled by niobium surface encapsulation. npj Quantum Inf. 10, 43 (2024).
Bilmes, A., Volosheniuk, S., Ustinov, A. V. & Lisenfeld, J. Probing defect densities at the edges and inside Josephson junctions of superconducting qubits. npj Quantum Inf. 8, 24 (2022).
Martinis, J. M. et al. Decoherence in Josephson qubits from dielectric loss. Phys. Rev. Lett. 95, 210503 (2005).
Mamin, H. J. et al. Merged-element transmons: design and qubit performance. Phys. Rev. Appl. 16, 024023 (2021).
Carroll, M., Rosenblatt, S., Jurcevic, P., Lauer, I. & Kandala, A. Dynamics of superconducting qubit relaxation times. npj Quantum Inf. 8, 132 (2022).
Barends, R. et al. Coherent Josephson qubit suitable for scalable quantum integrated circuits. Phys. Rev. Lett. 111, 080502 (2013).
Ambegaokar, V. & Baratoff, A. Tunneling between superconductors. Phys. Rev. Lett. 10, 486–489 (1963).
Osman, A. et al. Simplified Josephson-junction fabrication process for reproducibly high-performance superconducting qubits. Appl. Phys. Lett. 118, 064002 (2021).
Pishchimova, A. A. et al. Improving Josephson junction reproducibility for superconducting quantum circuits: junction area fluctuation. Sci. Rep. 13, 6772 (2023).
Moskalev, D. O. et al. Optimization of shadow evaporation and oxidation for reproducible quantum Josephson junction circuits. Sci. Rep. 13, 4174 (2023).
Koppinen, P. J., Väistö, L. M. & Maasilta, I. J. Complete stabilization and improvement of the characteristics of tunnel junctions by thermal annealing. Appl. Phys. Lett. 90, 053503 (2007).
Kim, H. et al. Effects of laser-annealing on fixed-frequency superconducting qubits. Appl. Phys. Lett. 121, 142601 (2022).
Pop, I. M. et al. Fabrication of stable and reproducible submicron tunnel junctions. J. Vac. Sci. Technol. B 30, 010607 (2012).
Shiota, T., Imamura, T. & Hasuo, S. Fabrication of high quality Nb/AlO/sub /x-Al/Nb Josephson junctions. III. Annealing stability of AlO/sub /x tunneling barriers. IEEE Trans. Appl. Supercond. 2, 222–227 (1992).
Hertzberg, J. B. et al. Laser-annealing Josephson junctions for yielding scaled-up superconducting quantum processors. npj Quantum Inf. 7, 129 (2021).
Van Damme, J. Advanced CMOS manufacturing of superconducting qubits on 300 mm wafers. Zenodo https://doi.org/10.5281/zenodo.13143313 (2024).
