Increasing and stabilizing the coherence of superconducting quantum circuits and resonators is of utmost importance for various technologies, ranging from quantum information processors to highly sensitive detectors of low-temperature radiation in astrophysics. A major source of noise in such devices is a bath of quantum two-level systems (TLSs) with broad distribution of energies, existing in disordered dielectrics and on surfaces. Here we study the dielectric loss of superconducting resonators in the presence of a periodic electric bias field, which sweeps near-resonant TLSs in and out of resonance with the resonator, resulting in a periodic pattern of Landau–Zener transitions. We show that at high sweep rates compared to the TLS relaxation rate, the coherent evolution of the TLS over multiple transitions yields a significant reduction in the dielectric loss relative to the intrinsic value. This behavior is observed both in the classical high-power regime and in the quantum single-photon regime, possibly suggesting a viable technique to dynamically decouple TLSs from a qubit.

对于各种技术，从量子信息处理器到天体物理学中的低温辐射的高灵敏度检测器，增加和稳定超导量子电路和谐振器的相干性至关重要。这种设备中的主要噪声源是存在于无序电介质中和表面上的，能量分布广泛的量子二级系统（TLS）池。在这里，我们研究了存在周期性电偏置场时超导谐振器的介电损耗，该周期电势使谐振器和谐振器之间的近谐振TLS扫出和扫出，从而形成了Landau-Zener跃迁的周期性模式。我们显示，与TLS松弛率相比，在高扫描率下，TLS在多个跃迁上的连贯演化相对于本征值可显着降低介电损耗。在经典的高功率方案和量子单光子方案中都可以观察到这种行为，这可能表明一种可行的技术可以将TLS与量子位动态解耦。