近日，瑞士苏黎世联邦理工学院的Matteo Fadel及其研究团队取得一项新进展。经过不懈努力，他们实现非线性机械振荡器中的量子压缩。相关研究成果已于2024年6月21日在国际知名学术期刊《自然—物理学》上发表。

该研究团队成功实现了与超导量子比特耦合的千兆赫频率机械谐振器在零点波动以下的压缩。这一突破是通过参数驱动量子比特来实现的，进而引发了一个有效的双声子驱动过程。此外，研究人员还进一步证明了谐振腔模式继承了与量子比特的非谐振耦合的非线性特征，且这一特性可以通过调控失谐来调节。

基于此，研究人员实现了一个机械压缩克尔振荡器，并在其中展示了具有魏格纳函数负性和高量子费雪信息的非高斯运动量子态的制备。这表明这项研究结果也可以应用于量子计量和传感。

据悉，机械自由度是连续变量量子信息处理和玻色子量子模拟的自然候选者。然而，这些应用需要在量子体系中进行压缩和非线性工程。

附：英文原文

Title: Quantum squeezing in a nonlinear mechanical oscillator

Author: Marti, Stefano, von Lpke, Uwe, Joshi, Om, Yang, Yu, Bild, Marius, Omahen, Andraz, Chu, Yiwen, Fadel, Matteo

Issue&Volume: 2024-06-21

Abstract: Mechanical degrees of freedom are natural candidates for continuous-variable quantum information processing and bosonic quantum simulations. However, these applications require the engineering of squeezing and nonlinearities in the quantum regime. Here we demonstrate squeezing below the zero-point fluctuations of a gigahertz-frequency mechanical resonator coupled to a superconducting qubit. This is achieved by parametrically driving the qubit, which results in an effective two-phonon drive. In addition, we show that the resonator mode inherits a nonlinearity from the off-resonant coupling with the qubit, which can be tuned by controlling the detuning. We, thus, realize a mechanical squeezed Kerr oscillator, in which we demonstrate the preparation of non-Gaussian quantum states of motion with Wigner function negativities and high quantum Fisher information. This shows that our results can also have applications in quantum metrology and sensing.

DOI: 10.1038/s41567-024-02545-6

Source: https://www.nature.com/articles/s41567-024-02545-6