2018/04/26 by Vlad Negnevitsky, Matteo Marinelli, Karan Mehta +6 · 136 citations
Computer Science · Physics and Astronomy · #Cluster state #Electrical engineering #Flux qubit #One-way quantum computer #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum computer #Quantum entanglement #Quantum error correction #Quantum information #Quantum mechanics #Quantum network #Quantum teleportation #Qubit #Superconducting quantum computing #Topology (electrical circuits) #Trapped ion quantum computer #physics.atom-ph #quant-ph
paper · pdf · doi:10.1038/s41586-018-0668-z
published in Nature 563(7732), 527-531 (Nature Portfolio) · 9 pages including methods, 6 figures; v2: typos and minor edits
arxiv created 2018/04/26 · openalex publication_date 2018/11/01 · arxiv updated 2018/11/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Quantum error correction will be essential for realizing the full potential of large-scale quantum information processing devices. Fundamental to its experimental realization is the repetitive detection of errors via projective measurements of quantum correlations among qubits, and correction using conditional feedback. Performing these tasks repeatedly requires a system in which measurement and feedback decision times are short compared to qubit coherence times, where the measurement reproduces faithfully the desired projection, and for which the measurement process has no detrimental effect on the ability to perform further operations. Here we demonstrate up to 50 sequential measurements of correlations between two beryllium-ion qubits using a calcium ion ancilla, and implement feedback which allows us to stabilize two-qubit subspaces as well as Bell states. Multi-qubit mixed-species gates are used to transfer information from qubits to the ancilla, enabling quantum state detection with negligible crosstalk to the stored qubits. Heating of the ion motion during detection is mitigated using sympathetic recooling. A key element of the experimental system is a powerful classical control system, which features flexible in-sequence processing to implement feedback control. The methods employed here provide a number of essential ingredients for scaling trapped-ion quantum computing, and provide new opportunities for quantum state control and entanglement-enhanced quantum metrology.