National Institute of Standards and Technology, Boulder, CO 80305, USA.
Department of Physics, University of Colorado, Boulder, CO 80309, USA.
Science. 2021 May 7;372(6542):622-625. doi: 10.1126/science.abf2998.
Quantum entanglement of mechanical systems emerges when distinct objects move with such a high degree of correlation that they can no longer be described separately. Although quantum mechanics presumably applies to objects of all sizes, directly observing entanglement becomes challenging as masses increase, requiring measurement and control with a vanishingly small error. Here, using pulsed electromechanics, we deterministically entangle two mechanical drumheads with masses of 70 picograms. Through nearly quantum-limited measurements of the position and momentum quadratures of both drums, we perform quantum state tomography and thereby directly observe entanglement. Such entangled macroscopic systems are poised to serve in fundamental tests of quantum mechanics, enable sensing beyond the standard quantum limit, and function as long-lived nodes of future quantum networks.
当不同的物体以如此高的相关性运动，以至于它们不能再被单独描述时，机械系统的量子纠缠就出现了。尽管量子力学大概适用于所有大小的物体，但随着质量的增加，直接观察纠缠变得具有挑战性，需要以极小的误差进行测量和控制。在这里，我们使用脉冲机电技术确定性地纠缠两个质量为 70 皮克的机械鼓膜。通过对两个鼓的位置和动量的量子限制测量，我们进行了量子态层析成像，从而直接观察到了纠缠。这种纠缠的宏观系统有望在量子力学的基本测试中发挥作用，使传感超越标准量子极限，并作为未来量子网络的长寿命节点。
