Realizing repeated quantum error correction in a distance-three surface code

By Sebastian Krinner, N. Lacroix, A. Remm, A. D. Paolo, É. Genois, C. Leroux, C. Hellings, S. Lazăr, François Swiadek, J. Herrmann and 6 more. Nature, 2021

820 citations recorded by the source corpus.

Quantum computers hold the promise of solving computational problems that are intractable using conventional methods1. For fault-tolerant operation, quantum computers must correct errors occurring owing to unavoidable decoherence and limited control accuracy2. Here we demonstrate quantum error correction using the surface code, which is known for its exceptionally high tolerance to errors3–6. Using 17 physical qubits in a superconducting circuit, we encode quantum information in a distance-three logical qubit, building on recent distance-two error-detection experiments7–9. In an error-correction cycle taking only 1.1 μs, we demonstrate the preservation of four cardinal states of the logical qubit. Repeatedly executing the cycle, we measure and decode both bit-flip and phase-flip error syndromes using a minimum-weight perfect-matching algorithm in an error-model-free approach and apply corrections in post-processing. We find a low logical error probability of 3% per cycle when rejecting experimental runs in which leakage is detected. The measured characteristics of our device agree well with a numerical model. Our demonstration of repeated, fast and high-performance quantum error-correction cycles, together with recent advances in ion traps10, support our understanding that fault-tolerant quantum computation will be practically realizable. By using 17 physical qubits in a superconducting circuit to encode quantum information in a surface-code logical qubit, fast (1.1 μs) and high-performance (logical error probability of 3%) quantum error-correction cycles are demonstrated.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/b2a57179e23d49b7c2ffe1ffb7fbb0713249d68f

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Citations in the corpus

Quantum error mitigation (2022, background): “Meanwhile other experiments have indeed demonstrated early-stage fault-tolerant potentials [see e.g. Abobeih et al. (2022); Egan et al. (2021); Google Quantum AI (2023); Krinner et al. (2022); Postler et al. (2022); Ryan-Anderson et al. (2022); and Takeda et al. (2022)].”
Logical quantum processor based on reconfigurable atom arrays (2023, background): “For this reason, deep circuits require repetitive error correction 6,88 to constantly remove errors and continuously benefit from, for example, the p 2 suppression.”
High-threshold and low-overhead fault-tolerant quantum memory (2023, background): “Whereas some sources of noise can be eliminated with better control 16 , materials 17 and shielding 18–20 , several other sources appear to be difficult if at all possible to remove.”
Quantum error correction below the surface code threshold (2024, neutral): “Overall, we find that addressing leakage is crucial to operating surface codes with transmon qubits [15, 33, 39].”