Quantum state preparation and tomography of entangled mechanical resonators
Quantum state preparation and tomography of entangled mechanical resonators
复制标题
DOI：
10.1038/s41586-022-04500-y
复制
发表时间：
2022-04-21
期刊：
影响因子：
64.8
通讯作者：
Safavi-Naeini, Amir H.
中科院分区：
文献类型：
--
作者：
Wollack, E. Alex;Cleland, Agnetta Y.;Safavi-Naeini, Amir H.
精确设计的机械振荡器可以计时、过滤信号并感知运动，使其成为当今技术格局中不可或缺的一部分。这些独特的能力促使机械设备通过与工程量子电路接口进入量子领域。将微波频率机械谐振器与超导装置联合收割机结合的提议提出了强大的量子声学处理器的可能性（1 - 3）。同时，在几个机械系统中的实验已经证明了量子态控制和读出（4，5），声子数分辨率（6，7）和声子介导的量子比特-量子比特相互作用（8，9）。目前，这些声学平台缺乏能够用单个量子比特控制若干机械振荡器的量子态的处理器，以及纠错所需的机械态的快速量子非破坏测量。在这里，我们使用超导量子比特来控制和读出一对纳米机械谐振器的量子态。我们的设备能够进行快速量子位力学交换操作，我们使用它来确定性地操纵机械状态。通过将量子比特同时置于两个机械谐振器的强色散区，我们通过Ramsey测量确定了谐振器的声子数分布。最后，我们提出了量子层析成像的准备非经典和纠缠的机械状态。我们的结果代表了一个具体的步骤，以反馈为基础的操作的量子声学处理器。
Precisely engineered mechanical oscillators keep time, filter signals and sense motion, making them an indispensable part of the technological landscape of today. These unique capabilities motivate bringing mechanical devices into the quantum domain by interfacing them with engineered quantum circuits. Proposals to combine microwave-frequency mechanical resonators with superconducting devices suggest the possibility of powerful quantum acoustic processors(1-3). Meanwhile, experiments in several mechanical systems have demonstrated quantum state control and readout(4,5), phonon number resolution(6,7) and phonon-mediated qubit-qubit interactions(8,9). At present, these acoustic platforms lack processors capable of controlling the quantum states of several mechanical oscillators with a single qubit and the rapid quantum non-demolition measurements of mechanical states needed for error correction. Here we use a superconducting qubit to control and read out the quantum state of a pair of nanomechanical resonators. Our device is capable of fast qubit-mechanics swap operations, which we use to deterministically manipulate the mechanical states. By placing the qubit into the strong dispersive regime with both mechanical resonators simultaneously, we determine the phonon number distributions of the resonators by means of Ramsey measurements. Finally, we present quantum tomography of the prepared nonclassical and entangled mechanical states. Our result represents a concrete step towards feedback-based operation of a quantum acoustic processor.