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arXiv:2408.13687quant-ph

Quantum error correction below the surface code threshold

Rajeev Acharya, Laleh Aghababaie-Beni, Igor Aleiner, Trond I. Andersen, Markus Ansmann, Frank Arute, Kunal Arya, Abraham Asfaw, Nikita Astrakhantsev, Juan Atalaya, Ryan Babbush, Dave Bacon, Brian Ballard, Joseph C. Bardin, Johannes Bausch, Andreas Bengtsson, Alexander Bilmes, Sam Blackwell, Sergio Boixo, Gina Bortoli, Alexandre Bourassa, Jenna Bovaird, Leon Brill, Michael Broughton, David A. Browne, Brett Buchea, Bob B. Buckley, David A. Buell, Tim Burger, Brian Burkett, Nicholas Bushnell, Anthony Cabrera, Juan Campero, Hung-Shen Chang, Yu Chen, Zijun Chen, Ben Chiaro, Desmond Chik, Charina Chou, Jahan Claes, Agnetta Y. Cleland, Josh Cogan, Roberto Collins, Paul Conner, William Courtney, Alexander L. Crook, Ben Curtin, Sayan Das, Alex Davies, Laura De Lorenzo, Dripto M. Debroy, Sean Demura, Michel Devoret, Agustin Di Paolo, Paul Donohoe, Ilya Drozdov, Andrew Dunsworth, Clint Earle, Thomas Edlich, Alec Eickbusch, Aviv Moshe Elbag, Mahmoud Elzouka, Catherine Erickson, Lara Faoro, Edward Farhi, Vinicius S. Ferreira, Leslie Flores Burgos, Ebrahim Forati, Austin G. Fowler, Brooks Foxen, Suhas Ganjam, Gonzalo Garcia, Robert Gasca, Élie Genois, William Giang, Craig Gidney, Dar Gilboa, Raja Gosula, Alejandro Grajales Dau, Dietrich Graumann, Alex Greene, Jonathan A. Gross, Steve Habegger, John Hall, Michael C. Hamilton, Monica Hansen, Matthew P. Harrigan, Sean D. Harrington, Francisco J. H. Heras, Stephen Heslin, Paula Heu, Oscar Higgott, Gordon Hill, Jeremy Hilton, George Holland, Sabrina Hong, Hsin-Yuan Huang, Ashley Huff, William J. Huggins, Lev B. Ioffe, Sergei V. Isakov, Justin Iveland, Evan Jeffrey, Zhang Jiang, Cody Jones, Stephen Jordan, Chaitali Joshi, Pavol Juhas, Dvir Kafri, Hui Kang, Amir H. Karamlou, Kostyantyn Kechedzhi, Julian Kelly, Trupti Khaire, Tanuj Khattar, Mostafa Khezri, Seon Kim, Paul V. Klimov, Andrey R. Klots, Bryce Kobrin, Pushmeet Kohli, Alexander N. Korotkov, Fedor Kostritsa, Robin Kothari, Borislav Kozlovskii, John Mark Kreikebaum, Vladislav D. Kurilovich, Nathan Lacroix, David Landhuis, Tiano Lange-Dei, Brandon W. Langley, Pavel Laptev, Kim-Ming Lau, Loïck Le Guevel, Justin Ledford, Kenny Lee, Yuri D. Lensky, Shannon Leon, Brian J. Lester, Wing Yan Li, Yin Li, Alexander T. Lill, Wayne Liu, William P. Livingston, Aditya Locharla, Erik Lucero, Daniel Lundahl, Aaron Lunt, Sid Madhuk, Fionn D. Malone, Ashley Maloney, Salvatore Mandrá, Leigh S. Martin, Steven Martin, Orion Martin, Cameron Maxfield, Jarrod R. McClean, Matt McEwen, Seneca Meeks, Anthony Megrant, Xiao Mi, Kevin C. Miao, Amanda Mieszala, Reza Molavi, Sebastian Molina, Shirin Montazeri, Alexis Morvan, Ramis Movassagh, Wojciech Mruczkiewicz, Ofer Naaman, Matthew Neeley, Charles Neill, Ani Nersisyan, Hartmut Neven, Michael Newman, Jiun How Ng, Anthony Nguyen, Murray Nguyen, Chia-Hung Ni, Thomas E. O'Brien, William D. Oliver, Alex Opremcak, Kristoffer Ottosson, Andre Petukhov, Alex Pizzuto, John Platt, Rebecca Potter, Orion Pritchard, Leonid P. Pryadko, Chris Quintana, Ganesh Ramachandran, Matthew J. Reagor, David M. Rhodes, Gabrielle Roberts, Eliott Rosenberg, Emma Rosenfeld, Pedram Roushan, Nicholas C. Rubin, Negar Saei, Daniel Sank, Kannan Sankaragomathi, Kevin J. Satzinger, Henry F. Schurkus, Christopher Schuster, Andrew W. Senior, Michael J. Shearn, Aaron Shorter, Noah Shutty, Vladimir Shvarts, Shraddha Singh, Volodymyr Sivak, Jindra Skruzny, Spencer Small, Vadim Smelyanskiy, W. Clarke Smith, Rolando D. Somma, Sofia Springer, George Sterling, Doug Strain, Jordan Suchard, Aaron Szasz, Alex Sztein, Douglas Thor, Alfredo Torres, M. Mert Torunbalci, Abeer Vaishnav, Justin Vargas, Sergey Vdovichev, Guifre Vidal, Benjamin Villalonga, Catherine Vollgraff Heidweiller, Steven Waltman, Shannon X. Wang, Brayden Ware, Kate Weber, Theodore White, Kristi Wong, Bryan W. K. Woo, Cheng Xing, Z. Jamie Yao, Ping Yeh, Bicheng Ying, Juhwan Yoo, Noureldin Yosri, Grayson Young, Adam Zalcman, Yaxing Zhang, Ningfeng Zhu, Nicholas Zobrist

Abstract

Quantum error correction provides a path to reach practical quantum computing by combining multiple physical qubits into a logical qubit, where the logical error rate is suppressed exponentially as more qubits are added. However, this exponential suppression only occurs if the physical error rate is below a critical threshold. In this work, we present two surface code memories operating below this threshold: a distance-7 code and a distance-5 code integrated with a real-time decoder. The logical error rate of our larger quantum memory is suppressed by a factor of $Λ$ = 2.14 $\pm$ 0.02 when increasing the code distance by two, culminating in a 101-qubit distance-7 code with 0.143% $\pm$ 0.003% error per cycle of error correction. This logical memory is also beyond break-even, exceeding its best physical qubit's lifetime by a factor of 2.4 $\pm$ 0.3. We maintain below-threshold performance when decoding in real time, achieving an average decoder latency of 63 $μ$s at distance-5 up to a million cycles, with a cycle time of 1.1 $μ$s. To probe the limits of our error-correction performance, we run repetition codes up to distance-29 and find that logical performance is limited by rare correlated error events occurring approximately once every hour, or 3 $\times$ 10$^9$ cycles. Our results present device performance that, if scaled, could realize the operational requirements of large scale fault-tolerant quantum algorithms.

arXiv comments
10 pages, 4 figures, Supplementary Information
Journal reference
Nature 638 (2025) 920-926
DOI
doi:10.1038/s41586-024-08449-y
Subjects
quant-phQuantum Physics

On Hacker News

Linked by 10 identifiable commenters in 14 comments across 8 threads, from Sep 2024 to Apr 2026. Found in 5 HN submissions from Aug 2024 to Dec 2024. Open submission discussions.

Comments linking this paper, per year.

Discussed in comments8 threads

  1. Securing Elliptic Curve Cryptocurrencies Against Quantum Vulnerabilities [pdf] 1 comment

    • > [0.1% gate error rate] is still wildly out of reach This is false. When Fowler et al assumed 0.1% gate error rates would be reached for his estimates in 2012 [0], that was ostentatious. Now it's frankly a bit overly conservative. All the big architectures are approaching or…

      StrilancView on HNParent context

  2. OpenSSH Post-Quantum Cryptography 1 comment

    • That paper is hilarious, and is correct that there's plenty of shit to make fun of... but there's also progress. I recommend watching Sam Jacques' talk from PQCrypto 2025 [0]. It would be silly to delay PQC adoption because of focusing on the irrelevant bad papers. In the past…

      StrilancView on HNParent context

  3. Why Quantum Cryptanalysis is Bollocks [pdf] 1 comment

    • Using the largest number factored as a benchmark for progress in quantum computing is like evaluating floor(f(0)) = 0 and floor(f(1)) = 0 and concluding f(x) = 0. You can't distinguish f(x) = 0 from f(x) = x/2 from f(x) = e^x/3 when your test is too coarse. If you want to see…

      StrilancView on HNParent context

  4. Willow, Our Quantum Chip 5 comments

    • Edit after skimming arxiv preprint[1]: Yeah, this is pretty huge. They achieved the result with surface codes, which are general ECCs. The repetition code was used to further probe quantum ECC floor. "Just POC" likely doesn't do it justice. (Original comment): Also quantum…

      winwangView on HNParent context

    • Some of these results have been on the arxiv for a few months (https://arxiv.org/abs/2408.13687) -- are there any details on new stuff besides this blog post? I can't find anything on the random circuit sampling in the preprint (or its early access published version).

      radioactivistView on HNParent context

    • It does. It's up to engineering to make errors uncorrelated. The google paper being referenced actually makes an "error budget" to see what the main sources of errors are, and also run tests to find sources of correlated errors. The claim about this is that correlated errors…

      wasabi991011View on HNParent context

    • I wouldn't call it extraordinary, as this has been expected since the first quantum error correcting codes were worked out theoretically. But it is a strong claim, backed up with comparably strong evidence. Figure 1d of the paper shows exactly this…

      qnleighView on HNParent context

    • and the arXiv preprint, which isn't paywalled https://arxiv.org/html/2408.13687v1

      qnleighView on HNParent context

  5. Understanding Google's Quantum Error Correction Breakthrough 3 comments

    • Note the paper they are referring to was published August 27, 2024 https://arxiv.org/pdf/2408.13687

      terminalbraidView on HNParent context

    • This is another hype piece from Google's research and development arm. This is a theoretical application to increase the number of logical qubits in a system by decreasing the error caused by quantum circuts. They just didn't do the last part yet so the application is yet to be…

      kittikittiView on HNParent context

    • This is not about AlphaQubit. It's about a different paper, https://arxiv.org/abs/2408.13687 and they do demonstrate real-time decoding. > we show that we can maintain below-threshold operation on the 72-qubit processor even when decoding in real time, meeting the strict timing…

      bramathonView on HNParent context

  6. IBM Quantum delivers on 2022 100x100 performance challenge 1 comment

    • I'm condensed matter theory PhD student and my research is close but not directly related to quantum computing. There are some usecases for quantum computers and we are pretty sure that QCs are able to do stuff classical ones can't, but it is somewhat limited. In fact there is…

      EvgeniyZhView on HNParent context

  7. Qubit Transistors Reach Error Correction Benchmark 1 comment

    • > I have not seen even a theoretical framework allowing both to be increased simultaneously. The threshold theorem [1], showing this can be done in principle, was proven more than a decade ago. But you don't have to believe the theory anymore, there's experiments now! Last month…

      StrilancView on HNParent context

  8. Quantum error correction below the surface code threshold 1 comment

    • "Quantum error correction below the surface code threshold" (2024) https://arxiv.org/abs/2408.13687 : > Abstract: Quantum error correction provides a path to reach practical quantum computing by combining multiple physical qubits into a logical qubit, where the logical error…

      westurnerView on HNParent context

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