Hardware-efficient quantum error correction via concatenated bosonic qubits

• 成果类型: Article
• 署名作者: Putterman, Harald; Noh, Kyungjoo; Hann, Connor T.; Maccabe, Gregory S.; Aghaeimeibodi, Shahriar; Patel, Rishi N.; Lee, Menyoung; Jones, William M.; Moradinejad, Hesam; Rodriguez, Roberto; Mahuli, Neha; Rose, Jefferson; Owens, John Clai; Levine, Harry; Rosenfeld, Emma; Reinhold, Philip; Moncelsi, Lorenzo; Alcid, Joshua Ari; Alidoust, Nasser; Arrangoiz-Arriola, Patricio; Barnett, James; Bienias, Przemyslaw; Carson, Hugh A.; Chen, Cliff; Chen, Li; Chinkezian, Harutiun; Chisholm, Eric M.; Chou, Ming-Han; Clerk, Aashish; Clifford, Andrew; Cosmic, R.; Curiel, Ana Valdes; Davis, Erik; Delorenzo, Laura; D'Ewart, J. Mitchell; Diky, Art; D'Souza, Nathan; Dumitrescu, Philipp T.; Eisenmann, Shmuel; Elkhouly, Essam; Evenbly, Glen; Fang, Michael T.; Fang, Yawen; Fling, Matthew J.; Fon, Warren; Garcia, Gabriel; Gorshkov, Alexey V.; Grant, Julia A.; Gray, Mason J.; Grimberg, Sebastian; Grimsmo, Arne L.; Haim, Arbel; Hand, Justin; He, Yuan; Hernandez, Mike; Hover, David; Hung, Jimmy S. C.; Hunt, Matthew; Iverson, Joe; Jarrige, Ignace; Jaskula, Jean-Christophe; Jiang, Liang; Kalaee, Mahmoud; Karabalin, Rassul; Karalekas, Peter J.; Keller, Andrew J.; Khalajhedayati, Amirhossein; Kubica, Aleksander; Lee, Hanho; Leroux, Catherine; Lieu, Simon; Ly, Victor; Madrigal, Keven Villegas; Marcaud, Guillaume; Mccabe, Gavin; Miles, Cody; Milsted, Ashley; Minguzzi, Joaquin; Mishra, Anurag; Mukherjee, Biswaroop; Naghiloo, Mahdi; Oblepias, Eric; Ortuno, Gerson; Pagdilao, Jason; Pancotti, Nicola; Panduro, Ashley; Paquette, Jp; Park, Minje; Peairs, Gregory A.; Perello, David; Peterson, Eric C.; Ponte, Sophia; Preskill, John; Qiao, Johnson; Refael, Gil; Resnick, Rachel; Retzker, Alex; Reyna, Omar A.; Runyan, Marc; Ryan, Colm A.; Sahmoud, Abdulrahman; Sanchez, Ernesto; Sanil, Rohan; Sankar, Krishanu; Sato, Yuki; Scaffidi, Thomas; Siavoshi, Salome; Sivarajah, Prasahnt; Skogland, Trenton; Su, Chun-Ju; Swenson, Loren J.; Teo, Stephanie M.; Tomada, Astrid; Torlai, Giacomo; Wollack, E. Alex; Ye, Yufeng; Zerrudo, Jessica A.; Zhang, Kailing; Brandao, Fernando G. S. L.; Matheny, Matthew H.; Painter, Oskar
• 署名单位: University of Chicago; California Institute of Technology; Hebrew University of Jerusalem; California Institute of Technology; Alphabet Inc.; Google Incorporated; Yale University; University of California System; University of California Irvine
• 刊物名称: Nature
• ISSN/ISSBN: 0028-2665
• DOI: 10.1038/s41586-025-08642-7
• 发表日期: 2025-02-27
• 关键词: states; CODES

摘要

To solve problems of practical importance1,2, quantum computers probably need to incorporate quantum error correction, in which a logical qubit is redundantly encoded in many noisy physical qubits3, 4-5. The large physical-qubit overhead associated with error correction motivates the search for more hardware-efficient approaches6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17-18. Here, using a superconducting quantum circuit19, we realize a logical qubit memory formed from the concatenation of encoded bosonic cat qubits with an outer repetition code of distance d = 5 (ref. 10). A stabilizing circuit passively protects cat qubits against bit flips20, 21, 22, 23-24. The repetition code, using ancilla transmons for syndrome measurement, corrects cat qubit phase flips. We study the performance and scaling of the logical qubit memory, finding that the phase-flip correcting repetition code operates below the threshold. The logical bit-flip error is suppressed with increasing cat qubit mean photon number, enabled by our realization of a cat-transmon noise-biased CX gate. The minimum measured logical error per cycle is on average 1.75(2)% for the distance-3 code sections, and 1.65(3)% for the distance-5 code. Despite the increased number of fault locations of the distance-5 code, the high degree of noise bias preserved during error correction enables comparable performance. These results, where the intrinsic error suppression of the bosonic encodings enables us to use a hardware-efficient outer error-correcting code, indicate that concatenated bosonic codes can be a compelling model for reaching fault-tolerant quantum computation.