论文标题
具有单光子占用率的可调微波腔中谐振频率的反馈稳定
Feedback stabilization of the resonant frequency in tunable microwave cavities with single-photon occupancy
论文作者
论文摘要
我们成功地证明了在单光子占用率下驱动的腔体库珀对晶体管（CCPT）的谐振频率波动中的低频噪声抑制。特别是，我们报告说，当腔驱动以平均光子数$ n = 10 $驱动时，内部电荷噪声在$ \ sim $ 1.4 kHz的带宽上降低了谐振频率波动，而平均$ n = 1 $的带宽为11 Hz。 CCPT的栅极依赖性可调性使我们能够实现源自磅 - 折线锁锁技术的反馈 - 安全性。由于固有的电荷噪声，这会减少波动，否则会干扰CCPT作为接近量子限制的电表的操作。我们认为，我们的技术可以被推广以实现可调微波谐振器中的频率稳定，这些谐振器在当今的量子计算体系结构中起着至关重要的作用，从而调节了该电路设备上内在的$ 1/f $ noise引起的检测限制。该工作讨论了与全功能反馈回路的操作相关的各个方面，直到单光子级。
We successfully demonstrate low-frequency noise suppression in the resonant frequency fluctuations of a cavity-embedded Cooper pair transistor (cCPT) driven at single-photon occupancy. In particular, we report a reduction in the resonant frequency fluctuations caused by the internal charge noise over a bandwidth of $\sim$1.4 kHz when the cavity is driven at an average photon number $n=10$, and a bandwidth of 11 Hz for average $n=1$. The gate-dependent tunability of the cCPT allows us to implement a feedback-scheme, derived from the Pound-Drever-Hall locking technique. This reduces fluctuations due to intrinsic charge-noise, which otherwise interferes with the cCPT's operation as a near quantum-limited electrometer. We believe our technique can be generalized to achieve frequency stabilization in tunable microwave resonators that play a vital role in today's quantum computing architecture, thereby moderating the limitations in detection caused by the intrinsic $1/f$-noise on such circuit devices. The work discusses the various aspects relating to the operation of a fully functional feedback loop down to the single-photon level.
