标题： 用射频超导量子比特探测宏观机械振荡器的量子运动 显示英文标题

标题： Probing the quantum motion of a macroscopic mechanical oscillator with a radio-frequency superconducting qubit

摘要： 像以兆赫兹频率振荡且在量子区域运行的鼓一样寿命长的机械谐振子，为量子技术和基础物理测试提供了一个强大的平台。 然而，对这些系统的量子控制仍然具有挑战性，特别是由于它们的能量尺度较低以及难以实现与其他良好控制的量子设备的有效耦合。 在这里，我们展示了在4 MHz悬浮硅氮化物膜和共振超导重费米子量子比特之间重复且高保真的相互作用。 该量子比特被初始化在一个有效温度为27~$\mathrm{\mu}$K，并以77%的保真度单次读出。 在膜的6毫秒寿命期间，这两个系统交换激发超过300次。 每次相互作用后，都会执行状态选择性检测，实施一系列弱测量的闪光序列，提供关于机械状态的信息。 累积记录重建了膜的位置噪声谱，揭示了其在10 mK时的热占据$n_\mathrm{th}\approx47$和量子比特引起的反作用。 通过在每次相互作用之前准备量子比特处于基态或激发态，我们观察到发射和吸收光谱之间的不平衡，分别与$n_\mathrm{th}$和$n_\mathrm{th}+1$成正比——这是声子产生和湮灭算符非对易性的标志。 由于预测的 Diósi-Penrose 引力坍缩时间与测量到的机械去相干时间相当，我们的架构进入了可以直接测试引力导致去相干的领域。 显示英文摘要

摘要： Long-lived mechanical resonators like drums oscillating at MHz frequencies and operating in the quantum regime offer a powerful platform for quantum technologies and tests of fundamental physics. Yet, quantum control of such systems remains challenging, particularly owing to their low energy scale and the difficulty of achieving efficient coupling to other well-controlled quantum devices. Here, we demonstrate repeated, and high-fidelity interactions between a 4 MHz suspended silicon nitride membrane and a resonant superconducting heavy-fluxonium qubit. The qubit is initialized at an effective temperature of 27~$\mathrm{\mu}$K and read out in a single-shot with 77% fidelity. During the membrane's 6~ms lifetime, the two systems swap excitations more than 300 times. After each interaction, a state-selective detection is performed, implementing a stroboscopic series of weak measurements that provide information about the mechanical state. The accumulated records reconstruct the membrane's position noise-spectrum, revealing both its thermal occupation $n_\mathrm{th}\approx47$ at 10~mK and the qubit-induced back-action. By preparing the qubit either in its ground or excited state before each interaction, we observe an imbalance between the emission and absorption spectra, proportional to $n_\mathrm{th}$ and $n_\mathrm{th}+1$, respectively-a hallmark of the non-commutation of phonon creation and annihilation operators. Since the predicted Di\'osi-Penrose gravitational collapse time is comparable to the measured mechanical decoherence time, our architecture enters a regime where gravity-induced decoherence could be tested directly.