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Dynamical decoupling of quantum two-level systems by coherent multiple Landau–Zener transitions
npj Quantum Information ( IF 6.6 ) Pub Date : 2019-12-18 , DOI: 10.1038/s41534-019-0228-x
Shlomi Matityahu , Hartmut Schmidt , Alexander Bilmes , Alexander Shnirman , Georg Weiss , Alexey V. Ustinov , Moshe Schechter , Jürgen Lisenfeld

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.



中文翻译:

量子二能级系统通过相干的多个Landau-Zener跃迁进行动态解耦

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。

更新日期:2019-12-18
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