论文标题
在超导谐振器中建模介电损耗：在NB/氧化物界面相互作用的原子两级系统的证据
Modelling dielectric loss in superconducting resonators: Evidence for interacting atomic two-level systems at the Nb/oxide interface
论文作者
论文摘要
尽管一些实验声称在无定形表面/接口中的两级系统（TLS）缺陷负责超导谐振器和Qubits中的能量放松，但没有一个人可以根据常规的非互动TLS模型来提供其数据的定量解释。在这里，提出了一个模型，该模型提出了相互作用和非相互作用的TLS损失切线，以对实验数据进行数值分析，并提取有关TLS参数及其分布的信息。作为原理的证明，该模型应用于特斯拉腔，其内部仅包含单个有损失材料的niobium/niobium氧化物界面。最佳拟合显示与薄（5 nm）和厚（100 nm）氧化物的电动偶极矩相互作用，表明TLSS是“原子”而不是“玻璃状”。该方法可以应用于具有多个材料界面和底物的其他设备，目的是阐明TLSS的性质，从而导致谐振器和Qubits的能量损失。
While several experiments claim that two-level system (TLS) defects in amorphous surfaces/interfaces are responsible for energy relaxation in superconducting resonators and qubits, none can provide quantitative explanation of their data in terms of the conventional noninteracting TLS model. Here a model that interpolates between the interacting and noninteracting TLS loss tangent is proposed to perform numerical analysis of experimental data and extract information about TLS parameters and their distribution. As a proof of principle, the model is applied to TESLA cavities that contain only a single lossy material in their interior, the niobium/niobium oxide interface. The best fits show interacting TLSs with a sharp modulus of electric dipole moment for both thin (5 nm) and thick (100 nm) oxides, indicating that the TLSs are "atomic" instead of "glassy". The proposed method can be applied to other devices with multiple material interfaces and substrates, with the goal of elucidating the nature of TLSs causing energy loss in resonators and qubits.
