Linke Norbert M, Gutierrez Mauricio, Landsman Kevin A, Figgatt Caroline, Debnath Shantanu, Brown Kenneth R, Monroe Christopher
Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, MD 20742, USA.
Schools of Chemistry and Biochemistry, Computational Science and Engineering, and Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Sci Adv. 2017 Oct 20;3(10):e1701074. doi: 10.1126/sciadv.1701074. eCollection 2017 Oct.
Quantum computers will eventually reach a size at which quantum error correction becomes imperative. Quantum information can be protected from qubit imperfections and flawed control operations by encoding a single logical qubit in multiple physical qubits. This redundancy allows the extraction of error syndromes and the subsequent detection or correction of errors without destroying the logical state itself through direct measurement. We show the encoding and syndrome measurement of a fault-tolerantly prepared logical qubit via an error detection protocol on four physical qubits, represented by trapped atomic ions. This demonstrates the robustness of a logical qubit to imperfections in the very operations used to encode it. The advantage persists in the face of large added error rates and experimental calibration errors.
量子计算机最终将达到一个规模，届时量子纠错将变得至关重要。通过在多个物理量子比特中编码单个逻辑量子比特，量子信息可以免受量子比特缺陷和有缺陷的控制操作的影响。这种冗余允许提取错误症候群，并随后检测或纠正错误，而无需通过直接测量破坏逻辑状态本身。我们通过对由捕获的原子离子表示的四个物理量子比特进行错误检测协议，展示了容错制备的逻辑量子比特的编码和症候群测量。这证明了逻辑量子比特对于用于编码它的操作中的缺陷具有鲁棒性。面对大幅增加的错误率和实验校准误差，这种优势依然存在。
