Department of Physics, Technical University of Denmark, Fysikvej 309, 2800 Kgs Lyngby, Denmark.
Australian Centre of Excellence for Engineered Quantum Systems, University of Queensland, St Lucia, Queensland 4072, Australia.
Nat Commun. 2016 Nov 29;7:13628. doi: 10.1038/ncomms13628.
Laser cooling is a fundamental technique used in primary atomic frequency standards, quantum computers, quantum condensed matter physics and tests of fundamental physics, among other areas. It has been known since the early 1990s that laser cooling can, in principle, be improved by using squeezed light as an electromagnetic reservoir; while quantum feedback control using a squeezed light probe is also predicted to allow improved cooling. Here we show the implementation of quantum feedback control of a micro-mechanical oscillator using squeezed probe light. This allows quantum-enhanced feedback cooling with a measurement rate greater than it is possible with classical light, and a consequent reduction in the final oscillator temperature. Our results have significance for future applications in areas ranging from quantum information networks, to quantum-enhanced force and displacement measurements and fundamental tests of macroscopic quantum mechanics.
激光冷却技术是一种在主要原子频率标准、量子计算机、量子凝聚态物理和基础物理检验等领域中应用的基本技术。自 20 世纪 90 年代初以来，人们已经知道，原则上可以通过使用压缩光作为电磁储备来改进激光冷却；同时，使用压缩光探针进行量子反馈控制也被预测可以允许更好的冷却效果。在这里，我们展示了使用压缩探针光对微机械振荡器进行量子反馈控制的实现。这使得可以通过比使用经典光更大的测量速率进行量子增强反馈冷却，并因此降低最终振荡器温度。我们的研究结果对于未来在量子信息网络、量子增强力和位移测量以及宏观量子力学的基础检验等领域的应用具有重要意义。
