利用克尔非线性抑制腔频率噪声
Suppressing Cavity Frequency Noise Using a Kerr Nonlinearity
浏览论文内容
中文总结 AI 辅助
该研究针对超导微波腔的频率噪声问题，利用克尔非线性的固有反馈机制，通过克尔锁定实现腔频率稳定，将波动降低近两个数量级，有望应用于多种量子相关系统。
中文摘要 AI 辅助
共振频率波动会限制用于量子比特读出、光机械位移传感和磁通量探测的超导微波腔的灵敏度与稳定性。本文展示了通过将噪声非线性超导微波腔锁定到强泵浦音来抑制共振频率波动的方法。该系统的克尔非线性使共振频率取决于腔内场振幅，产生了无需主动外部反馈的被动稳定固有反馈机制。我们采用双音光谱法对该固有非线性反馈机制进行实验表征，并通过艾伦偏差分析研究其时间稳定性。被锁定腔模的频率波动降低了近两个数量级，达到1/f噪声基底，且无需连续频率跟踪或主动控制。克尔锁定为自稳定非线性微波谐振器提供了通用方法，可抑制低频腔噪声同时保持对锁定带宽外信号的灵敏度，该方法有望惠及包括基于SQUID的谐振器、光机械器件和参数放大器在内的广泛系统。
英文摘要
Resonance-frequency fluctuations can limit the sensitivity and stability of superconducting microwave cavities used for qubit readout, optomechanical displacement sensing, and magnetic flux detection. Here, we demonstrate the suppression of resonance-frequency fluctuations by locking a noisy nonlinear superconducting microwave cavity to a strong pump tone. The Kerr nonlinearity of this system, whereby the resonance frequency depends on the intracavity field amplitude, gives rise to an intrinsic feedback mechanism that enables passive stabilization without active external feedback. Using two-tone spectroscopy, we experimentally characterize the intrinsic nonlinear feedback mechanism and investigate its temporal stability through Allan deviation analysis. The frequency fluctuations of the locked cavity mode are reduced by nearly two orders of magnitude, reaching the $1/f$ noise floor, without continuous frequency tracking or active control. Kerr locking provides a general approach for self-stabilizing nonlinear microwave resonators by suppressing low-frequency cavity noise while preserving sensitivity to signals outside the locking bandwidth. This approach may benefit a broad range of systems, including SQUID-based resonators, optomechanical devices, and parametric amplifiers.
