Satzinger K J, Zhong Y P, Chang H-S, Peairs G A, Bienfait A, Chou Ming-Han, Cleland A Y, Conner C R, Dumur É, Grebel J, Gutierrez I, November B H, Povey R G, Whiteley S J, Awschalom D D, Schuster D I, Cleland A N
Department of Physics, University of California, Santa Barbara, CA, USA.
Institute for Molecular Engineering, University of Chicago, Chicago, IL, USA.
Nature. 2018 Nov;563(7733):661-665. doi: 10.1038/s41586-018-0719-5. Epub 2018 Nov 21.
One of the hallmarks of quantum physics is the generation of non-classical quantum states and superpositions, which has been demonstrated in several quantum systems, including ions, solid-state qubits and photons. However, only indirect demonstrations of non-classical states have been achieved in mechanical systems, despite the scientific appeal and technical utility of such a capability, including in quantum sensing, computation and communication applications. This is due in part to the highly linear response of most mechanical systems, which makes quantum operations difficult, as well as their characteristically low frequencies, which hinder access to the quantum ground state. Here we demonstrate full quantum control of the mechanical state of a macroscale mechanical resonator. We strongly couple a surface acoustic-wave resonator to a superconducting qubit, using the qubit to control and measure quantum states in the mechanical resonator. We generate a non-classical superposition of the zero- and one-phonon Fock states and map this and other states using Wigner tomography. Such precise, programmable quantum control is essential to a range of applications of surface acoustic waves in the quantum limit, including the coupling of disparate quantum systems.
量子物理学的一个标志是产生非经典量子态和叠加态，这已在包括离子、固态量子比特和光子在内的多个量子系统中得到证实。然而，尽管这种能力在科学上具有吸引力且在技术上具有实用性，包括在量子传感、计算和通信应用中，但在机械系统中仅实现了非经典态的间接证明。部分原因在于大多数机械系统的高度线性响应，这使得量子操作变得困难，以及它们特有的低频，这阻碍了对量子基态的获取。在此，我们展示了对宏观机械谐振器机械状态的完全量子控制。我们将表面声波谐振器与一个超导量子比特强耦合，利用该量子比特来控制和测量机械谐振器中的量子态。我们生成了零声子和一声子福克态的非经典叠加态，并使用维格纳断层扫描对该态及其他态进行映射。这种精确的、可编程的量子控制对于表面声波在量子极限下的一系列应用至关重要，包括不同量子系统的耦合。
