Hardware-efficient quantum error correction using concatenated bosonic qubits

Hardware-efficient quantum error correction using concatenated bosonic qubits

In order to solve problems of practical importance, quantum computers will likely need to incorporate quantum error correction, where a logical qubit is redundantly encoded in many noisy physical qubits. The large physical-qubit overhead typically associated with error correction motivates the searc...

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Main Authors: Putterman, Harald, Hann, Connor T, Aghaeimeibodi, Shahriar, Patel, Rishi N, Lee, Menyoung, Moradinejad, Hesam, Rodriguez, Roberto, Rose, Jefferson, Levine, Harry, Rosenfeld, Emma, Reinhold, Philip, Moncelsi, Lorenzo, Alcid, Joshua Ari, Alidoust, Nasser, Barnett, James, Bienias, Przemyslaw, Carson, Hugh A, 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, Fon, Warren, 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, Madrigal, Keven Villegas, Marcaud, Guillaume, McCabe, Gavin, Miles, Cody, Milsted, Ashley, Minguzzi, Joaquin, Mishra, Anurag, Mukherjee, Biswaroop, Naghiloo, Mahdi, Ortuno, Gerson, Pagdilao, Jason, Pancotti, Nicola, 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, Sahmoud, Abdulrahman, Sanchez, Ernesto, Sanil, Rohan, Sankar, Krishanu, Scaffidi, Thomas, Siavoshi, Salome, Sivarajah, Prasahnt, Teo, Stephanie M, Tomada, Astrid, Torlai, Giacomo, Wollack, E. Alex, Ye, Yufeng, Zhang, Kailing, Brandão, Fernando G. S. L, Matheny, Matthew H, Painter, Oskar
Format: Journal Article
Language:English
Published: 19-09-2024
Subjects:
Physics - Quantum Physics
Online Access:Get full text
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Summary:In order to solve problems of practical importance, quantum computers will likely need to incorporate quantum error correction, where a logical qubit is redundantly encoded in many noisy physical qubits. The large physical-qubit overhead typically associated with error correction motivates the search for more hardware-efficient approaches. Here, using a microfabricated superconducting quantum circuit, we realize a logical qubit memory formed from the concatenation of encoded bosonic cat qubits with an outer repetition code of distance $d=5$. The bosonic cat qubits are passively protected against bit flips using a stabilizing circuit. Cat-qubit phase-flip errors are corrected by the repetition code which uses ancilla transmons for syndrome measurement. We realize a noise-biased CX gate which ensures bit-flip error suppression is maintained during error correction. We study the performance and scaling of the logical qubit memory, finding that the phase-flip correcting repetition code operates below threshold, with logical phase-flip error decreasing with code distance from $d=3$ to $d=5$. Concurrently, the logical bit-flip error is suppressed with increasing cat-qubit mean photon number. 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 longer distance-5 code, demonstrating the effectiveness of bit-flip error suppression throughout the error correction cycle. These results, where the intrinsic error suppression of the bosonic encodings allows us to use a hardware-efficient outer error correcting code, indicate that concatenated bosonic codes are a compelling paradigm for reaching fault-tolerant quantum computation.
DOI:10.48550/arxiv.2409.13025