A macroscopic object passively cooled into its quantum ground state of motion beyond single-mode cooling.
A macroscopic object passively cooled into its quantum ground state of motion beyond single-mode cooling.
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DOI：
10.1038/s41467-021-26457-8
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发表时间：
2021-10-26
影响因子：
16.6
通讯作者：
Collin E
中科院分区：
文献类型：
--
作者：
Cattiaux D;Golokolenov I;Kumar S;Sillanpää M;Mercier de Lépinay L;Gazizulin RR;Zhou X;Armour AD;Bourgeois O;Fefferman A;Collin E
量子与经典交叉的本质仍然是迄今为止科学中最具挑战性的开放性问题之一。在这方面，移动的物体起着特定的作用。在过去的几年里，开创性的实验已经开始探索微米级机械系统的量子行为，要么通过被动冷却单GHz模式，要么通过采用原子物理学中开发的激光冷却技术来冷却远低于其周围温度的特定低频模式。在这里，我们描述了一种非常不同的方法，将整个微机械系统被动冷却到500 μK，将15 MHz时基本振动模式中的平均量子数减少到0.3（更高谐波的数值甚至更低）；挑战在于仍然能够在不明显干扰系统的情况下检测到运动。通过这种方法，高次谐波和周围环境也被冷却，从而可能导致更长的机械相干时间，并使实验能够质疑机械波函数坍缩，可能来自引力背景和量子热力学。除了平均行为之外，这里我们还报告了与低温恒温器平衡的设备的基本振动模式的波动。这些揭示了与当地环境令人惊讶的复杂相互作用，并允许探测两个不同热力学浴的特征。与主动技术相比，机械模式的被动冷却可以使设备与环境保持平衡，而不会产生过多的阻尼。在这里，作者展示了15 μm的具有MHz基本弯曲的鼓头器件的被动冷却和热化到其量子基态。
The nature of the quantum-to-classical crossover remains one of the most challenging open question of Science to date. In this respect, moving objects play a specific role. Pioneering experiments over the last few years have begun exploring quantum behaviour of micron-sized mechanical systems, either by passively cooling single GHz modes, or by adapting laser cooling techniques developed in atomic physics to cool specific low-frequency modes far below the temperature of their surroundings. Here instead we describe a very different approach, passive cooling of a whole micromechanical system down to 500 μK, reducing the average number of quanta in the fundamental vibrational mode at 15 MHz to just 0.3 (with even lower values expected for higher harmonics); the challenge being to be still able to detect the motion without disturbing the system noticeably. With such an approach higher harmonics and the surrounding environment are also cooled, leading to potentially much longer mechanical coherence times, and enabling experiments questioning mechanical wave-function collapse, potentially from the gravitational background, and quantum thermodynamics. Beyond the average behaviour, here we also report on the fluctuations of the fundamental vibrational mode of the device in-equilibrium with the cryostat. These reveal a surprisingly complex interplay with the local environment and allow characteristics of two distinct thermodynamic baths to be probed. Compared to active techniques, passive cooling of mechanical modes allows to work with devices in equilibrium with their environment without excess damping. Here, the authors demonstrate passive cooling and thermalisation of a 15 μm drum-head device with MHz fundamental flexure to its quantum ground state.
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影响因子：
64.8
作者：
Chan, Jasper;Mayer Alegre, T. P.;Painter, Oskar
通讯作者：
Painter, Oskar
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作者：
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