Journal Article

Real-time quantum error correction beyond break-even

Singh, S., Ding, A. Z., Sivak, V. V., Devoret, M. H., Frunzio, L., Girvin, S. M., Eickbusch, A., Ganjam, S., Brock, B. L., Tsioutsios, I., Miano, A., Schoelkopf, R. J., Royer, B.

2023

Overview

The ambition of harnessing the quantum for computation is at odds with the fundamental phenomenon of decoherence. The purpose of quantum error correction (QEC) is to counteract the natural tendency of a complex system to decohere. This cooperative process, which requires participation of multiple quantum and classical components, creates a special type of dissipation that removes the entropy caused by the errors faster than the rate at which these errors corrupt the stored quantum information. Previous experimental attempts to engineer such a process 1 – 7 faced the generation of an excessive number of errors that overwhelmed the error-correcting capability of the process itself. Whether it is practically possible to utilize QEC for extending quantum coherence thus remains an open question. Here we answer it by demonstrating a fully stabilized and error-corrected logical qubit whose quantum coherence is substantially longer than that of all the imperfect quantum components involved in the QEC process, beating the best of them with a coherence gain of G  = 2.27 ± 0.07. We achieve this performance by combining innovations in several domains including the fabrication of superconducting quantum circuits and model-free reinforcement learning. A study demonstrates the extension of a lifetime of a quantum memory using active quantum error correction and reinforcement learning.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 639/766/483/2802 / 639/766/483/481 / CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS / Codes / Coherence / Complex systems / CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY / Entropy / Error correction / Error correction & detection / Fabrication / Humanities and Social Sciences / multidisciplinary / NANOSCIENCE AND NANOTECHNOLOGY / Quantum computing / quantum information / Quantum phenomena / qubits / Qubits (quantum computing) / Science / Science (multidisciplinary)