2020/04/30 by Jeffrey M. Gertler, Brian Baker, Juliang Li +3 · 6 citations
Computer Science · Physics and Astronomy · #Coherence (philosophical gambling strategy) #Dissipation #Emulation #Error detection and correction #Mechanical and Optical Resonators #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum computer #Quantum error correction #Quantum information #Qubit #quant-ph
paper · pdf · doi:10.1038/s41586-021-03257-0
published as Nature 590, 243-248 (2021) · Approximately 5 pages of main text, 4 figures
openalex created_date 2020/04/24 · arxiv created 2020/10/06 · openalex publication_date 2021/02/10 · arxiv updated 2021/02/16 · openalex updated_date 2026/08/05
To build a universal quantum computer from fragile physical qubits, effective implementation of quantum error correction (QEC) is an essential requirement and a central challenge. Existing demonstrations of QEC are based on a schedule of discrete error syndrome measurements and adaptive recovery operations. These active routines are hardware intensive, prone to introducing and propagating errors, and expected to consume a vast majority of the processing power in a large-scale quantum computer. In principle, QEC can be realized autonomously and continuously by tailoring dissipation within the quantum system, but this strategy has remained challenging so far. Here we encode a logical qubit in Schrödinger cat-like multiphoton states of a superconducting cavity, and demonstrate a corrective dissipation process that directly stabilizes an error syndrome operator: the photon number parity. Implemented with continuous-wave control fields only, this passive protocol realizes autonomous correction against single-photon loss and boosts the coherence time of the multiphoton qubit by over a factor of two. Notably, QEC is realized in a modest hardware setup with neither high-fidelity readout nor fast digital feedback, in contrast to the technological sophistication required for prior QEC demonstrations. Compatible with other error suppression and phase stabilization techniques, our experiment suggests reservoir engineering as a resource-efficient alternative or supplement to active QEC in future quantum computing architectures.