马约拉纳量子比特中化学势变化导致的零温泄漏
Leakage at zero temperature from changes in chemical potential in Majorana qubits
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中文总结 AI 辅助
研究发现马约拉纳tetron量子比特在零温下因化学势微小变化导致错误率随长度线性增长，源于泄漏到激发态并毒化马约拉纳模式，由半朗道-齐纳效应描述，需进一步研究缓解策略。
中文摘要 AI 辅助
构建容错量子计算机需要具有极低错误率的物理量子比特。基于马约拉纳的tetron量子比特预计其错误率随拓扑超导线的逆温度和长度呈指数下降。与这一预测相反，我们表明在零温下，由化学势微小变化引起的错误随tetron长度线性增长。这些错误源于泄漏到激发准粒子态，最终毒化tetron两端的马约拉纳模式，导致错误。我们进一步证明，这种泄漏的动力学由半朗道-齐纳效应描述，该效应决定了其对关键系统参数的依赖，如超导能隙、化学势变化以及马约拉纳模式空间轮廓的动态变化。这些结果激励了对泄漏对量子比特性能影响及潜在缓解策略的进一步研究。
英文摘要
Building a fault-tolerant quantum computer requires physical qubits with exceptionally low error rates. Majorana-based tetron qubits are predicted to exhibit error rates that decrease exponentially with inverse temperature and length of each topological superconducting wire in the tetron. In contrast to this prediction, we show that errors arising from small variations in the chemical potential grow linearly with tetron length at zero temperature. These errors stem from leakage into excited quasiparticle states, which ultimately poison Majorana modes at opposite ends of the tetron, causing errors. We further demonstrate that the dynamics of this leakage is captured by the half Landau-Zener effect, which dictates its dependence on key system parameters such as the superconducting gap, chemical potential variations, and dynamic changes in the spatial profile of Majorana modes. These results motivate further investigations into the impact of leakage on qubit performance and potential mitigation strategies.
