论文标题
克服可扩展量子误差校正中的泄漏
Overcoming leakage in scalable quantum error correction
论文作者
论文摘要
量子信息从计算状态中泄漏到高能状态中是追求量子误差校正（QEC）的主要挑战。在QEC电路中，泄漏会随着时间的推移而建立，并通过多数相互作用扩散。这会导致相关的误差，从而将逻辑误差的指数抑制降低，从而挑战了QEC作为通往容忍失误量子计算的途径的可行性。在这里，我们演示了距离3的表面代码和距离-21位 - 翼型量子代码的执行。这缩短了泄漏的寿命，并减少了其传播和引起相关错误的能力。我们报告了编码逻辑状态的数据量数的稳态泄漏人群的降低，并且在整个设备中平均泄漏人群低于$ 1 \ times 10^{ - 3} $。泄漏清除过程本身有效地将泄漏总体返回到计算基础上，并将其添加到代码电路中，可以防止泄漏在周期中引起相关误差，从而恢复了QEC的基本假设。通过证明可以包含泄漏的证明，我们解决了大规模实用QEC的关键挑战。
Leakage of quantum information out of computational states into higher energy states represents a major challenge in the pursuit of quantum error correction (QEC). In a QEC circuit, leakage builds over time and spreads through multi-qubit interactions. This leads to correlated errors that degrade the exponential suppression of logical error with scale, challenging the feasibility of QEC as a path towards fault-tolerant quantum computation. Here, we demonstrate the execution of a distance-3 surface code and distance-21 bit-flip code on a Sycamore quantum processor where leakage is removed from all qubits in each cycle. This shortens the lifetime of leakage and curtails its ability to spread and induce correlated errors. We report a ten-fold reduction in steady-state leakage population on the data qubits encoding the logical state and an average leakage population of less than $1 \times 10^{-3}$ throughout the entire device. The leakage removal process itself efficiently returns leakage population back to the computational basis, and adding it to a code circuit prevents leakage from inducing correlated error across cycles, restoring a fundamental assumption of QEC. With this demonstration that leakage can be contained, we resolve a key challenge for practical QEC at scale.
