A cascaded random access quantum memory - Nature

Nature Physics (2026) Cite this article Dynamic random access memory is critical to classical computing but notably absent in current superconducting quantum processors. Integrating high-coherence memory units would enable resource-efficient control of logical qubits and allow the separate optimization of logic and storage subsystems. Here we realize an eight-bit cascaded random access quantum memory. We use a single transmon to classically address seven memory modes while isolating them from processor nonlinearities by introducing a buffer layer between the processor and a multimode storage cavity. We demonstrate arbitrary random access with an average infidelity of less than 1.5% per mode and characterize the many-body interactions that dominate the error budget. This architecture enables a significant reduction in control lines per logical qubit and supports transversal operations within the memory module, establishing a scalable unit cell for fault-tolerant quantum architectures. This is a preview of subscription content, access via your institution Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription $32.99 / 30 days cancel any timeSubscribe to this journal Receive 12 print issues and online access $259.00 per yearonly $21.58 per issueBuy this articleUSD 39.95Prices may be subject to local taxes which are calculated during checkoutAll data used within this Article are available from the corresponding author upon request. Source data are provided with this paper. These data are also available via figshare at https://doi.org/10.6084/m9.figshare.32736012 (ref. 49).Simulation codes are available via figshare at https://doi.org/10.6084/m9.figshare.32736012 (ref. 49). All other codes used within this Article are available from the corresponding author upon request.Ofek, N. et al. Extending the lifetime of a quantum bit with error correction in superconducting circuits. Nature 536, 441 (2016).Article ADS Google Scholar Takeda, K., Noiri, A., Nakajima, T., Kobayashi, T. & Tarucha, S. Quantum error correction with silicon spin qubits. Nature 608, 682 (2022).Article ADS Google Scholar Ryan-Anderson, C. et al. Realization of real-time fault-tolerant quantum error correction. Phys. Rev. X 11, 041058 (2021).

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The transmon chip was fabricated in the Pritzker Nanofabrication Facility at the University of Chicago, which receives support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205), a node of the National Science Foundation’s National Nanotechnology Coordinated Infrastructure. This work also made use of the shared facilities at the University of Chicago Materials Research Science and Engineering Center, supported by the National Science Foundation under award number DMR-2011854. The coupler chip was fabricated at the Stanford Nano Shared Facilities (SNSF) RRID: SCR023230, supported by the National Science Foundation under award ECCS-2026822. We acknowledge all the other members of the Schuster Lab for discussions and technical support.The authors disclose support for the research of this work from the Air Force Office of Scientific Research (AFOSR) MURI (grant numbers FA9550-19-1-0399, FA9550-21-1-0209 and FA9550-23-1-0338) and from the Samsung Advanced Institute of Technology Global Research Partnership. E.G. discloses support for the research of this work from the National Science Foundation Graduate Research Fellowship Program (NSF GRFP).These authors contributed equally: Ziqian Li, Eesh Gupta.Department of Physics and Applied Physics, Stanford University, Stanford, CA, USAZiqian Li, Eesh Gupta & David I. SchusterDepartment of Physics, University of Chicago, Chicago, IL, USAZiqian Li, Riju Banerjee & Andrew OrianiSLAC National Accelerator Laboratory, Menlo Park, CA, USAZiqian Li, Eesh Gupta & David I. SchusterFermi National Accelerator Laboratory, Batavia, IL, USAFang Zhao, Yao Lu & Tanay RoyCenter for Quantum Information Physics, Department of Physics, New York University, New York, NY, USAAndrei VrajitoareaDepartment of Physics and Astronomy, Rutgers University, Piscataway, NJ, USASrivatsan ChakramSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarThese authors contributed equally: Z.L., E.G., Z.L., E.G. and D.I.S. conceived the experiment. R.B., A.O. and S.C. designed and machined the flute cavity. Z.L. and F.Z. designed the transmon qubit, which F.Z. fabricated. Z.L., R.B., F.Z. and E.G. designed the on-chip filter. Z.L. and E.G. designed the balun in discussion with A.V., and designed the SQUID coupler in discussion with Y.L.; Z.L. and E.G. also fabricated the coupler. T.R. designed the parametric amplifiers, which F.Z. fabricated. Z.L. and E.G. calibrated the experiment, analysed the data and performed the simulations. D.I.S. supervised all aspects of the project. Z.L., E.G. and D.I.S. wrote the manuscript, with input from all authors.Correspondence to David I. Schuster.The authors declare no competing interests.Nature Physics thanks Sofia Gonzalez-Garcia, Luyan Sun and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.Supplementary Figs. 1–12, Discussion and Tables 1–10.Frequency and coherence data for all modes.Single mode swap RB fidelities.RAQM benchmarking.Error budget.Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.Reprints and permissionsLi, Z., Gupta, E., Zhao, F. et al. A cascaded random access quantum memory. Nat. Phys. (2026). https://doi.org/10.1038/s41567-026-03418-wDownload citationReceived: 06 January 2026Accepted: 21 July 2026Published: 08 September 2026Version of record: 08 September 2026DOI: https://doi.org/10.1038/s41567-026-03418-wAnyone you share the following link with will be able to read this content:Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative