Repeated quantum error detection in a surface code

By C. K. Andersen, A. Remm, S. Lazăr, Sebastian Krinner, N. Lacroix, G. Norris, M. Gabureac, Christopher Eichler, Andreas Wallraff. Nature Physics, 2019

314 citations recorded by the source corpus.

The realization of quantum error correction is an essential ingredient for reaching the full potential of fault-tolerant universal quantum computation. Using a range of different schemes, logical qubits that are resistant to errors can be redundantly encoded in a set of error-prone physical qubits. One such scalable approach is based on the surface code. Here we experimentally implement its smallest viable instance, capable of repeatedly detecting any single error using seven superconducting qubits—four data qubits and three ancilla qubits. Using high-fidelity ancilla-based stabilizer measurements, we initialize the cardinal states of the encoded logical qubit with an average logical fidelity of 96.1%. We then repeatedly check for errors using the stabilizer readout and observe that the logical quantum state is preserved with a lifetime and a coherence time longer than those of any of the constituent qubits when no errors are detected. Our demonstration of error detection with its resulting enhancement of the conditioned logical qubit coherence times is an important step, indicating a promising route towards the realization of quantum error correction in the surface code. In a surface code consisting of four data and three ancilla qubits, repeated error detection is demonstrated. The lifetime and coherence time of the logical qubit are enhanced over those of any of the constituent qubits when no errors are detected.

Subfields: Artificial Intelligence, Computational Theory and Mathematics

View Paper: https://www.semanticscholar.org/paper/527db080e1f4715dfa04e083f386ec897ddca53f

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Citations in the corpus

Realizing repeated quantum error correction in a distance-three surface code (2021, background): “[7] for up to five quantum-error-detection cycles.”
Demonstration of fault-tolerant universal quantum gate operations (2021, background): “State preparation of a topological surface code state [14], repetitive stabilizer measurements in an error-detecting surface code [15, 16] and exponential error suppression in a repetition code [17] have been demonstrated in super-conducting architectures.”
Engineered dissipation for quantum information science (2022, methodology): “The surface code has been proposed as a practical approach to large-scale quantum computation 120 , tolerating single qubit error rates comparable to current experimental limits 20,121 and scalable with current qubit architectures 122 .”