Frequency instability of superconducting resonators and qubits leads to dephasing and time-varying energy loss and hinders quantum processor tune-up. Its main source is dielectric noise originating in surface oxides. Thorough noise studies are needed to develop a comprehensive understanding and mitigation strategy of these fluctuations. We use a frequency-locked loop to track the resonant frequency jitter of three different resonator types—one niobium nitride superinductor, one aluminum coplanar waveguide, and one aluminum cavity—and we observe notably similar random telegraph signal fluctuations. At low microwave drive power, the resonators exhibit multiple, unstable frequency positions, which, for increasing power, coalesce into one frequency due to motional narrowing caused by sympathetic driving of two-level system defects by the resonator. In all three devices, we identify a dominant fluctuator whose switching amplitude (separation between states) saturates with increasing drive power, but whose characteristic switching rate follows the power law dependence of quasi-classical Landau-Zener transitions.

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超导谐振器的稳定性：运动变窄和朗道-齐纳驱动两能级缺陷的作用

超导谐振器和量子比特的频率不稳定性会导致失相和随时间变化的能量损失，并阻碍量子处理器的调整。其主要来源是源自表面氧化物的介电噪声。需要进行彻底的噪声研究，以制定对这些波动的全面理解和缓解策略。我们使用锁频环来跟踪三种不同谐振器类型（一种氮化铌超电感器、一种铝共面波导和一种铝腔）的谐振频率抖动，我们观察到非常相似的随机电报信号波动。在低微波驱动功率下，谐振器表现出多个不稳定的频率位置，为了增加功率，由于谐振器对两能级系统缺陷的共感驱动引起的运动变窄，这些位置合并为一个频率。