Demonstrating a long-coherence dual-rail erasure qubit using tunable transmons

• Main Authors: Levine, Harry, Haim, Arbel, Hung, Jimmy S. C, Alidoust, Nasser, DeLorenzo, Laura, Wollack, E. Alex, Arrangoiz-Arriola, Patricio, Khalajhedayati, Amirhossein, Sanil, Rohan, Moradinejad, Hesam, Vaknin, Yotam, Kubica, Aleksander, Hover, David, Aghaeimeibodi, Shahriar, Alcid, Joshua Ari, Baek, Christopher, Barnett, James, Bawdekar, Kaustubh, Carson, Hugh, Chen, Cliff, Chen, Li, Chinkezian, Harut, Chisholm, Eric M, Clifford, Andrew, Crisosto, Nicole, Dalzell, Alexander M, Davis, Erik, D'Ewart, J. Mitch, Diez, Sandra, D'Souza, Nathan, Elkhouly, Essam, Fang, Michael, Fang, Yawen, Flammia, Steven T, Fling, Matthew J, Garcia, Gabriel, Gharzai, M. Kabeer, Gorshkov, Alexey V, Gray, Mason J, Grimsmo, Arne L, Hann, Connor T, He, Yuan, Heidel, Steven, Howell, Sean, Hunt, Matthew, Iverson, Joseph K, Jarrige, Ignace, Jiang, Liang, Jones, William M, Karabalin, Rassul, Karalekas, Peter J, Keller, Andrew J, Ly, Victor, MacCabe, Gregory S, Mahuli, Neha, Marcaud, Guillaume, Matheny, Matthew H, McArdle, Sam, Merton, Gabe, Miles, Cody, Milsted, Ashley, Mishra, Anurag, Moncelsi, Lorenzo, Naghiloo, Mahdi, Noh, Kyungjoo, Oblepias, Eric, Ortuno, Gerson, Owens, John Clai, Panduro, Ashley, Patel, Rishi N, Peairs, Gregory A, Perello, David J, Peterson, Eric C, Ponte, Sophia, Putterman, Harald, Refael, Gil, Reinhold, Philip, Resnick, Rachel, Reyna, Omar A, Rodriguez, Roberto, Rose, Jefferson, Rubin, Alex H, Runyan, Marc, Ryan, Colm A, Sahmoud, Abdulrahman, Shah, Bhavik, Siavoshi, Salome, Sivarajah, Prasahnt, Skogland, Trenton, Su, Chun-Ju, Swenson, Loren J, Sylvia, Jared, Tomada, Astrid, Torlai, Giacomo, Wistrom, Mark, Zhang, Kailing, Zuk, Ido, Clerk, Aashish A, Brandão, Fernando G. S. L, Retzker, Alex
• Format: Journal Article
• Language: English
• Published: 20-03-2024
• Subjects: Physics - Quantum Physics
• DOI: 10.48550/arxiv.2307.08737

Physical Review X 14, 011051 (2024) Quantum error correction with erasure qubits promises significant advantages
over standard error correction due to favorable thresholds for erasure errors.
To realize this advantage in practice requires a qubit for which nearly all
errors are such erasure errors, and the ability to check for erasure errors
without dephasing the qubit. We demonstrate that a "dual-rail qubit" consisting
of a pair of resonantly coupled transmons can form a highly coherent erasure
qubit, where transmon $T_1$ errors are converted into erasure errors and
residual dephasing is strongly suppressed, leading to millisecond-scale
coherence within the qubit subspace. We show that single-qubit gates are
limited primarily by erasure errors, with erasure probability $p_\text{erasure}
= 2.19(2)\times 10^{-3}$ per gate while the residual errors are $\sim 40$ times
lower. We further demonstrate mid-circuit detection of erasure errors while
introducing $< 0.1\%$ dephasing error per check. Finally, we show that the
suppression of transmon noise allows this dual-rail qubit to preserve high
coherence over a broad tunable operating range, offering an improved capacity
to avoid frequency collisions. This work establishes transmon-based dual-rail
qubits as an attractive building block for hardware-efficient quantum error
correction.