Cavity Optomechanics for Condensed Matter Physics

凝聚态物理的进步紧随测量技术的进步，而在过去的十年里，测量技术的进步没有比腔光学机械更大的了。腔光机械(机电)描述了光学(微波)腔与机械谐振器的工程耦合，这导致光子和声子之间的散射率显著提高，从而决定了机械运动。腔光学力学正被用来测试量子力学的极限，开发令人惊叹的新量子技术，但令人惊讶的是，几乎没有人将其应用于凝聚态物理的研究。在过去的12年里，我的团队在低温下发展了腔光学力学技术，并开始了一个雄心勃勃的计划，即对量子凝聚态物质进行腔光学力学研究，特别是针对超导体和超流体。我们是扭转光学机械领域的世界领先集团，并实现了创纪录的扭矩灵敏度。在目前的提议下，我们将扩展我们的光学机械扭矩平台，对单个超导涡旋进行实时测量，并首次观察超导体中涡旋晶格的集体动力学。这将使首次研究巨型多重量子化涡旋等异常现象的时间动力学，观察涡旋构型之间的转变，并探索非传统超导体。此外，我们的团队还开发了一个基于独特的超流体机电谐振器的先进平台，用于研究纳米尺度的超流体。在这里，我们计划利用这个平台来观察超流中的单激发，并进一步深入到2D领域来探索拓扑物理，如Kosterlitz-Thouless相变和2D涡旋。我们还将使用我们的超流机电谐振器来研究限制对超流3He的影响。我们已经建造了加拿大唯一的绝热核退磁制冷机，以达到超流体3He所需的亚毫克尔文温度。结合我们的2D技术，我们将探索一种新的超流态，我们最近首次绘制了相图，它被认为是一种‘超流晶体’，或对密度波态。我们还将探索超流3He中奇异的拓扑缺陷，并通过工程限制来稳定其他新相，这是量子流体中最重要的主题。从长远来看，我们将利用我们的低温和纳米制造专业知识，以及腔光学机械，来探索量子凝聚态的一些最深层次的问题，例如揭示非传统超导体中的配对态；探索拓扑超流体中的成对密度波态、Majorana费米子和超对称类物理；以及搜索最后未发现的元素超流体。

Advances in condensed matter physics closely follow advances in measurement technology, and there is no greater advance in measurement technology over the last decade than that of cavity optomechanics. Cavity optomechanics (electromechanics) describes the engineered coupling of an optical (microwave) cavity to a mechanical resonator, which leads to a dramatic improvement in the scattering rate between photons and phonons, and hence determination of the mechanical motion. Cavity optomechanics is being used to test the limits of quantum mechanics and develop amazing new quantum technologies, but surprisingly has barely been applied to the study of condensed matter physics. Over the last 12 years, my group has advanced the techniques of cavity optomechanics at low temperatures and is set to embark on an ambitious program of cavity optomechanical studies of quantum condensed matter, specifically targeting superconductors and superfluids. We are the world leading group in torsional optomechanics and have achieved a record setting torque sensitivity. Under the current proposal, we will extend our optomechanical torque platform to perform real-time measurements of individual superconducting vortices, and observe the collective dynamics of a vortex lattice in a superconductor for the first time. This will allow study of the temporal dynamics of unusual phenomena such as giant multiply quantized vortices for the first time, watch the transitions between vortex configurations, and explore unconventional superconductors. In addition, our group has developed an advanced platform for the study of superfluids confined to the nanoscale based on a unique superfluid electromechanical resonator. Here, we propose to use this platform to observe single excitations in the superfluid, and push deeper into the 2D realm to explore topological physics such as the Kosterlitz-Thouless transition and 2D vortices. We will also use our superfluid electromechanical resonator to study the effects of confinement on superfluid 3He. We have built Canada's only adiabatic nuclear demagnetization refrigerator to achieve the sub-millikelvin temperatures required for superfluid 3He. Combined with our 2D technology we will explore a new superfluid state, that we recently mapped out the phase diagram for the first time, which is believed to be a `superfluid crystal', or pair-density wave state. We will also explore exotic topological defects in superfluid 3He, and work to stabilize other new phases via engineered confinement, arguably the most important topics in quantum fluids. Long term, we will use our cryogenic and nanofabrication expertise, with cavity optomechanics, to explore some of the deepest questions of quantum condensed matter, such as uncovering the pairing state in unconventional superconductors; exploring pair-density wave states, Majorana fermions, and supersymmetry-like physics in topological superfluids; and searching for the last undiscovered elemental superfluid.