PME Special Quantum Seminar: Harry Levine, AWS Center for Quantum Computing
- When:
- Tuesday, August 8, 2023 10:00 am - 11:00 am
- Where:
- ERC 201B, William Eckhardt Research Center, 5640 S. Ellis Ave., Chicago, IL
- Title:
- Demonstrating a long-coherence dual-rail erasure qubit using tunable transmons
- Description:
-
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 T1 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 (0.219(2)% per gate) while the residual error rates are ~ 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.