椭圆形共振畸变作为铌超导谐振器中准粒子加热效应的特征
Oval-shaped resonance distortion as a signature of quasiparticle heating effect in a niobium superconducting resonator
浏览论文内容
中文总结 AI 辅助
研究超导微波谐振器在特定耗散机制下的非线性行为，通过修改方程建立 QPH 模型，发现复平面共振圆中的椭圆形畸变可作实验特征，经实验验证该模型，确认 QPH 机制是耗散非线性主要来源。
中文摘要 AI 辅助
我们研究了受耗散机制影响的超导微波谐振器的非线性行为，该机制下品质因数（Q 因子）随耗散功率增加而降低，产生耗散反馈效应。通过修改 Rothwarf-Taylor 方程，建立了宏观准粒子加热（QPH）模型，将品质因数与微波读出功率直接联系起来。关键发现是在复平面的共振圆中识别出独特的椭圆形畸变。在其他非线性机制足够弱的条件下，这种畸变可作为识别 QPH 主导损耗的读出功率范围的实际实验特征。为验证模型，设计并制造了铌（Nb）半波长共面波导（CPW）谐振器，进行了系统的浴温与读出功率扫描。该模型在广泛的操作条件下与观察到的椭圆形共振圆畸变拟合良好，证实 QPH 机制是所研究参数空间中耗散非线性的主要来源。
英文摘要
We investigate the nonlinear behavior of a superconducting microwave resonator subjected to a dissipative mechanism where the associated quality factor (Q factor) decreases with increasing dissipated power, leading to a dissipative feedback effect. By modifying the Rothwarf-Taylor equations, we establish a macroscopic quasiparticle heating (QPH) model that directly links the quality factor to the microwave readout power. The key finding is the identification of a distinctive oval-shaped distortion in the resonance circle in the complex plane. This distortion serves as a practical experimental signature for identifying the readout power regime in which QPH dominates the loss, under conditions where other nonlinear mechanisms are sufficiently weak. To validate the model, we design and fabricate a niobium (Nb) half-wavelength coplanar waveguide (CPW) resonator and conduct systematic bath temperature and readout power sweeps. The model provides a well fit to the observed oval-shaped resonance circle distortion across a wide range of operating conditions, confirming the QPH mechanism as the primary source of the dissipative non-linearity in the parameter space investigated.
